Bug 1392877

Description of problem:
When using incorrect data center path (import VM dialog), EngineException (code = 65) is logged in engine.log instead of logging that data center could not be found under this path.
In vdsm.log, the next log message appears:
jsonrpc.Executor/2::ERROR::2016-11-08 11:24:16,407::v2v::151::root::(get_external_vms) error connection to hypervisor: "internal error: Could not find datacenter specified in '/Compute55/Cluster55/10x.xxx.xxx.xxx'"

Version-Release number of selected component (if applicable):
ovirt-engine-4.0.5.5-0.1.el7ev
vdsm-4.18.15.2-1.el7ev.x86_64
qemu-kvm-rhev-2.6.0-27.el7.x86_64
libvirt-client-2.0.0-10.el7.x86_64
virt-v2v-1.32.7-3.el7.x86_64

How reproducible:
100%

Steps to Reproduce:
1. Browse webadmin -> virtual machines tab -> import dialog
2. select VMware provider and insert incorrect data center path
3. Click "load" button

Actual results:
- Import dialog failed with the next message: 
"Failed to communicate with the external provider, see log for additional details."
- the next exception is logged in engine.log:
2016-11-08 14:04:07,285 ERROR [org.ovirt.engine.core.bll.GetVmsFromExternalProviderQuery] (default task-14) [] Exception: org.ovirt.engine.core.common.errors.EngineException: EngineException: org.ovirt.engine.core.vdsbroker.vdsbroker.VDSErrorException: VDSGenericException: VDSErrorException: Failed to GetVmsFromExternalProviderVDS, error = internal error: Could not find datacenter specified in '/Folder1/Folder2/Compute3/Folder4/Cluster5/10x.xxx.xxx.xxx', code = 65 (Failed with error unexpected and code 16)

Expected results:
EngineException log should be replaced with "Could not find datacenter specified in '/Compute..."

Additional info:
engine.log (14:04:07,285) and vdsm.log (14:04:07,252) attached.