core: Removed AddSelfPermissionCommand

This command is unused, and it does not seem to have any meaningful
content, and thus can be removed.

This patch removes the following:
1. The MigrateIrsSnapshotsRoVdcCommand class
2. The corresponding constant in VdcActionType

Change-Id: I479e62b29570b8e6c3b7fec811efd58b50a5dc86
Signed-off-by: Allon Mureinik <amureini@redhat.com>
core: Remove unused ExportCandaidateVDSCommand

ExportCandidateVDSCommand was not used anywhere in the code, and should
thus be removed.

This patch removes the following:
1. The ExportCandidateVDSCommand class
2. The corresponding ExportCandidateVDSCommandParameters class
3. The corresponding ExportCandidate constant in VDSCommandType
4. The exportCandidate method from
   IIrsServer/IrsServerConnector/IrsServerWrapper

Change-Id: I7bfcdf24b05a7e90fe4a2d1b536c5a927297fd16
Signed-off-by: Allon Mureinik <amureini@redhat.com>
core: Remove validateStorageServerConnection

After change I7b3bc2491943a6daa21228e37169c83f32865984 removed all
usages of the validateStorageServerConnection method from the engine's
code, this patch removes the method itself.

Change-Id: I2d87168e52e3b9df15418cbf3a6693ae00214de4
Signed-off-by: Allon Mureinik <amureini@redhat.com>