core: Removed redundant storage allocation checks

AddVmCommandTest contains storage allocation checks.
StorageDomainValidator already has the necessary tests, so there's no need for
this redundancy. Therefore removing storage tests from AddVmCommandTest.

Change-Id: Ia0e28f6cc8bd2834d6fe6ce6288a20946a69e9b3
Related-to: https://bugzilla.redhat.com/show_bug.cgi?id=917682
Related-to: https://bugzilla.redhat.com/show_bug.cgi?id=1053742
Signed-off-by: Vered Volansky <vvolansk@redhat.com>
core: Reorganize SD space validations in AddVm

This is the first of two patches meant to fix faulty storage space
allocations validations in the different add VM commands.
This patch keeps the current (faulty) validations and reorganizes them
in methods that can be overridden in the derived classes when needed.
It also adds two new threshold tests - verifying the AddVmCommand
behaviour to the simulated
StorageDomainValidator.isDomainWithinThresholds .

Change-Id: I482709d7edb0333a6aa7b9ab723eea7f4c5a00d3
Related-to: https://bugzilla.redhat.com/show_bug.cgi?id=917682
Related-to: https://bugzilla.redhat.com/show_bug.cgi?id=1053742
Signed-off-by: Vered Volansky <vvolansk@redhat.com>
core: Fix AddVm faulty storage allocation checks

Fix AddVmCommand and its descendants storage allocation checks.
Amended and added relevant tests.
Note that the tests here rely on the fact that StorageDomainValidator is
well tested, and only simulate its output, then testing the commands
according to it.

Change-Id: Iff4ad246934b3b94f21ae602067033347c913780
Bug-Url: https://bugzilla.redhat.com/917682
Bug-Url: https://bugzilla.redhat.com/1053742
Signed-off-by: Vered Volansky <vvolansk@redhat.com>