Print an error/warning message, when a user tries to add 2 vaults to the server.

A user is able to define the vault on 2 different places in the EAP:
 - /core-service=vault:add(...)
 - /subsystem=security/vault=classic:add(...)

If both of them are defined, then no error/warning is displayed. The user can then use a value from the latter entry for instance to protect password in a datasource (again without any warning).

He will only see following exception during next server start:

15:23:08,207 ERROR [org.jboss.as.controller.management-operation] (ServerService Thread Pool -- 25) JBAS014612: Operation ("enable") failed - address: ([
    ("subsystem" => "datasources"),
    ("data-source" => "ExampleDS")
]): java.lang.SecurityException: JBAS013311: Security Exception
	at org.jboss.as.security.vault.RuntimeVaultReader.retrieveFromVault(RuntimeVaultReader.java:104)
	at org.jboss.as.server.RuntimeExpressionResolver.resolvePluggableExpression(RuntimeExpressionResolver.java:45)
	at org.jboss.as.controller.ExpressionResolverImpl.resolveExpressionType(ExpressionResolverImpl.java:115) [jboss-as-controller-7.3.0.Final-redhat-14.jar:7.3.0.Final-redhat-14]
	at org.jboss.as.controller.ExpressionResolverImpl.resolveExpressionsRecursively(ExpressionResolverImpl.java:58) [jboss-as-controller-7.3.0.Final-redhat-14.jar:7.3.0.Final-redhat-14]
	at org.jboss.as.controller.ExpressionResolverImpl.resolveExpressions(ExpressionResolverImpl.java:40) [jboss-as-controller-7.3.0.Final-redhat-14.jar:7.3.0.Final-redhat-14]
	at org.jboss.as.controller.ModelControllerImpl.resolveExpressions(ModelControllerImpl.java:588) [jboss-as-controller-7.3.0.Final-redhat-14.jar:7.3.0.Final-redhat-14]
	at org.jboss.as.controller.OperationContextImpl.resolveExpressions(OperationContextImpl.java:796) [jboss-as-controller-7.3.0.Final-redhat-14.jar:7.3.0.Final-redhat-14]
	at org.jboss.as.controller.ParallelBootOperationContext.resolveExpressions(ParallelBootOperationContext.java:340) [jboss-as-controller-7.3.0.Final-redhat-14.jar:7.3.0.Final-redhat-14]
	at org.jboss.as.controller.AttributeDefinition$1.resolveExpressions(AttributeDefinition.java:298) [jboss-as-controller-7.3.0.Final-redhat-14.jar:7.3.0.Final-redhat-14]
	at org.jboss.as.controller.AttributeDefinition.resolveValue(AttributeDefinition.java:362) [jboss-as-controller-7.3.0.Final-redhat-14.jar:7.3.0.Final-redhat-14]
	at org.jboss.as.controller.AttributeDefinition.resolveModelAttribute(AttributeDefinition.java:321) [jboss-as-controller-7.3.0.Final-redhat-14.jar:7.3.0.Final-redhat-14]
	at org.jboss.as.controller.AttributeDefinition.resolveModelAttribute(AttributeDefinition.java:295) [jboss-as-controller-7.3.0.Final-redhat-14.jar:7.3.0.Final-redhat-14]
	at org.jboss.as.connector.util.ModelNodeUtil.getResolvedStringIfSetOrGetDefault(ModelNodeUtil.java:33)
	at org.jboss.as.connector.subsystems.datasources.DataSourceModelNodeUtil.from(DataSourceModelNodeUtil.java:149)
	at org.jboss.as.connector.subsystems.datasources.DataSourceEnable.addServices(DataSourceEnable.java:166)
	at org.jboss.as.connector.subsystems.datasources.DataSourceEnable$1.execute(DataSourceEnable.java:95)
	at org.jboss.as.controller.AbstractOperationContext.executeStep(AbstractOperationContext.java:607) [jboss-as-controller-7.3.0.Final-redhat-14.jar:7.3.0.Final-redhat-14]
	at org.jboss.as.controller.AbstractOperationContext.doCompleteStep(AbstractOperationContext.java:485) [jboss-as-controller-7.3.0.Final-redhat-14.jar:7.3.0.Final-redhat-14]
	at org.jboss.as.controller.AbstractOperationContext.completeStepInternal(AbstractOperationContext.java:282) [jboss-as-controller-7.3.0.Final-redhat-14.jar:7.3.0.Final-redhat-14]
	at org.jboss.as.controller.AbstractOperationContext.executeOperation(AbstractOperationContext.java:277) [jboss-as-controller-7.3.0.Final-redhat-14.jar:7.3.0.Final-redhat-14]
	at org.jboss.as.controller.ParallelBootOperationStepHandler$ParallelBootTask.run(ParallelBootOperationStepHandler.java:343) [jboss-as-controller-7.3.0.Final-redhat-14.jar:7.3.0.Final-redhat-14]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) [rt.jar:1.7.0_45]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) [rt.jar:1.7.0_45]
	at java.lang.Thread.run(Thread.java:744) [rt.jar:1.7.0_45]
	at org.jboss.threads.JBossThread.run(JBossThread.java:122) [jboss-threads-2.1.1.Final-redhat-1.jar:2.1.1.Final-redhat-1]
Caused by: org.jboss.security.vault.SecurityVaultException: java.lang.IllegalArgumentException: Null input buffer
	at org.picketbox.plugins.vault.PicketBoxSecurityVault.retrieve(PicketBoxSecurityVault.java:279)
	at org.jboss.as.security.vault.RuntimeVaultReader.getValue(RuntimeVaultReader.java:129)
	at org.jboss.as.security.vault.RuntimeVaultReader.getValueAsString(RuntimeVaultReader.java:112)
	at org.jboss.as.security.vault.RuntimeVaultReader.retrieveFromVault(RuntimeVaultReader.java:102)
	... 24 more
Caused by: java.lang.IllegalArgumentException: Null input buffer
	at javax.crypto.Cipher.doFinal(Cipher.java:2083) [jce.jar:1.7.0_10]
	at org.picketbox.util.EncryptionUtil.decrypt(EncryptionUtil.java:134)
	at org.picketbox.plugins.vault.PicketBoxSecurityVault.retrieve(PicketBoxSecurityVault.java:275)
	... 27 more


Commands to reproduce the issue:

keytool -genseckey -alias vault -storetype jceks -keyalg AES -keysize 128 -storepass vault22 -keypass vault22 -dname CN=localhost, OU=JBoss Middleware, O=Red Hat, L=Brno, C=CZ -keystore /home/jcacek/test/vault/vault.keystore

./vault.sh -a passa -b exampleds -e /home/jcacek/test/vault -i 22 -k /home/jcacek/test/vault/vault.keystore -p vault22 -s 87654321 -v vault -x sa
./vault.sh -a passb -b exampleds -e /home/jcacek/test/vault2 -i 22 -k /home/jcacek/test/vault2/vault.keystore -p vault22 -s 87654321 -v vault -x sa

CLI:
/core-service=vault:add(vault-options=[("KEYSTORE_URL" => "/home/jcacek/test/vault/vault.keystore"), ("KEYSTORE_PASSWORD" => "MASK-Ci5JS1kjxPX"), ("KEYSTORE_ALIAS" => "vault"), ("SALT" => "87654321"),("ITERATION_COUNT" => "22"), ("ENC_FILE_DIR" => "/home/jcacek/test/vault/")])
/subsystem=security/vault=classic:add(vault-options=[("KEYSTORE_URL" => "/home/jcacek/test/vault2/vault.keystore"), ("KEYSTORE_PASSWORD" => "MASK-Ci5JS1kjxPX"), ("KEYSTORE_ALIAS" => "vault"), ("SALT" => "87654321"),("ITERATION_COUNT" => "22"), ("ENC_FILE_DIR" => "/home/jcacek/test/vault2/")])

[standalone@localhost:9999 /] /subsystem=datasources/data-source=ExampleDS:write-attribute(name=password, value=expression "${VAULT::exampleds::passa::1}") 
{                                                                                        
    "outcome" => "failed",
    "failure-description" => "JBAS014749: Operation handler failed: JBAS013311: Security Exception",
    "rolled-back" => true
}
[standalone@localhost:9999 /] /subsystem=datasources/data-source=ExampleDS:write-attribute(name=password, value=expression "${VAULT::exampleds::passb::1}")
{
    "outcome" => "success",
    "response-headers" => {
        "operation-requires-reload" => true,
        "process-state" => "reload-required"
    }
}