core: Fix vm_pools dynamic query

This fix will improve the dynamic query behavior when querying from vm_pool
based on primary key query.

Change-Id: I1f91cf3986e6f981e66b5ffd11b478fc1e724a4a
Bug-Url: https://bugzilla.redhat.com/1066392
Signed-off-by: lzelkha@redhat.com <lzelkha@redhat.com>