Comment 7 for bug 1413119

Agreed that the instance might have gone to ERROR state. Or it seemed to be toggling between ERROR and ACTIVE state (see log below)
But in any case, if this code method is being hit in case memory_mb being zero, then I reckon a minor change should be implemented to handle it.

Please move the bug back to working state.

Log:
2014-10-06 17:19:07.936 3882 WARNING NV-43FB562 Failed to compute_task_migrate_server: NV-78D5611 Migration pre-check error: NV-37B7976 Unable to migrate 352122ae-1ca1-43b3-8ba6-709d93fd580c to 9117MMB_100DBCP: Lack of memory(host:65536 <= instance:0)
2014-10-06 17:19:07.938 3882 WARNING NV-EAF7DD6 Setting instance to ACTIVE state.