core: use runInternalQuery for internal invocation

Following commit Ia5536d123b6407acf41b6946dde796bd67d1e073,
replaced 'runQuery' with 'runInternalQuery' in
GetVmsByStorageDomainQuery -> getAllDisksByStorageDomain.

Currently, invoking the query, throws USER_IS_NOT_LOGGED_IN
exception.

Change-Id: I5a6c2df41eba609b6b19e2a3be9e54ea8589df33
Signed-off-by: Daniel Erez <derez@redhat.com>