Description of problem:
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If none of the servers are defined in "host.xml" (means <servers></servers> empty tag is present) and if the user tries to run the following CLI command to change the "directory-grouping" to  "by-type"  then the value is not persisted in the configuration file (host.xml) and the <servers></servers>  tag is also removed from the host.xml

/host=master/:write-attribute(name=directory-grouping,value=by-type)

The value of "directory-grouping" is stored "in memory" so this change does not survive the host restart.



Version-Release number of selected component (if applicable):
JBoss Enterprise Application Platform 6.2.0

How reproducible:
===============
Steps to Reproduce:
1). Take a defaule JBoss EAP 6.2 installation and Start JBoss in domain mode. 

2). Remove the default servers. 

/host=master/server-config=server-one/:stop
/host=master/server-config=server-one/:remove
/host=master/server-config=server-two/:stop
/host=master/server-config=server-two/:remove
/host=master/server-config=server-three/:stop
/host=master/server-config=server-three/:remove

3). Check the "host.xml" file the empty <servers></servers> tag is present.

4) Apply the directory-grouping configuration.

/host=master/:write-attribute(name=directory-grouping,value=by-type)

5). Check the "host.xml", It can be seen that the <servers></servers> tag is removed.  As the "directory-grouping" information is not persisted in the XML file hence it is lost when we restart the Host controller.


Actual results:
==================
In "host.xml" file the "directory-grouping" should have persisted so that it could survive the host restart.



Expected results:


Additional info: