core: Fix canDoActionFailedUpdateReadOnly Test

In UpdateVmDiskCommandTest, above test assigned RO=true property to
existing disk-vm configuration ("oldDisk in the command"), which is irrelevant to the
test. This fix removes the above assignment and adds the relevant one - to
the new configuration.

Change-Id: Ic304ab235776b3db823522a9219a00d7c8df1017
Relates-To: https://bugzilla.redhat.com/1092087
Relates-To: https://bugzilla.redhat.com/1092371
Signed-off-by: Vered Volansky <vvolansk@redhat.com>
core: Disallow RO disks resize in CDA

Resizing RO disks is now disallowed in
UpdateVmDiskCommad.validateCanResizeDisk(), which is called by CDA.
Added VdcBllMessages.ACTION_TYPE_FAILED_CANNOT_RESIZE_READ_ONLY_DISK and
relevant test.

Change-Id: Ibd1b9ec592cacab0156bdede6081b375b7dae935
Bug-Url: https://bugzilla.redhat.com/1092087
Bug-Url: https://bugzilla.redhat.com/1092371
Signed-off-by: Vered Volansky <vvolansk@redhat.com>