core: LiveMigrateDisk - check isRunningOrPaused VMStatus

LiveMigrateDiskCommand - check isRunningOrPaused VMStatus instead of
isUpOrPaused [to prevent command failure when the VM changes
running status (e.g. RebootInProgress) while live migrating)].

Change-Id: I546dbe5e225ee0db5ca190d3237b70c5a425e004
Bug-Url: https://bugzilla.redhat.com/923992
Signed-off-by: Daniel Erez <derez@redhat.com>