core: LSM without context

LiveMigrateVmDisksCommand did not have a c'tor without CommandContext,
which made it impossible to use LSM.

Change-Id: I55ac1cc3b234a56a5d269ab4ebaeac528a3190de
Bug-Url: http://bugzilla.redhat.com/1116031
Signed-off-by: Vered Volansky <vvolansk@redhat.com>
core: use updated storage allocation validation

StorageDomainValidator.hasSpaceForClonedDisks() was introduced to the
system in commit 53b5eba699a695edc5b2e963e28b43ea5290b299 in order to
align all storage allocation checks throughout the system. This patch
applies above validation instead of the existing one
LiveMigrateVmDisksCommand.

Change-Id: I886967b7c2dadbbd301eadbea0c7eac9992aba08
Signed-off-by: Vered Volansky <vvolansk@redhat.com>
core: AddLSM source sd allocation validation

In LiveMigrateVmDisksCommand - added space allocation validation in the
source domains. A snapshot is taken on the source domain before actual migration.
Therefore source domains should have enough space for a new active image,
a fact verified by this patch.

Also changed relevant error message to not contain the word "target" to
suggest target storage domain since the same validation message is set for both
source and target storage domains. Note the message includes the name of
the specific storage domain, so this should do.

Change-Id: I1914f5efe50d2f5a4fb9debf0c0bde4ffc9e32eb
Bug-Url: https://bugzilla.redhat.com/1099894
Signed-off-by: Vered Volansky <vvolansk@redhat.com>
core: changed method call for readability

In LiveMigrateVmDisksCommand, changed calls to  parameters.getStorageDomainId
to paramaters.getTargetStorageDomainId for readability.
The latter's impelementation only  calls the former.

Change-Id: Id1c95635d602094a7d5babb532f4e79038c43039
Signed-off-by: Vered Volansky <vvolansk@redhat.com>
core: simplify isSameSourceAndDest

Simplified LiveMigrateVmDisksCommand.isSameSourceAndDest() 's implementation.

Change-Id: Ie5c32734d517f27230efd7ea67d4841d55d2c8ec
Signed-off-by: Vered Volansky <vvolansk@redhat.com>