core: Singleton row mapper for AdGroups

Added a singleton row mapper for AdGroupsDAO, as specified by
http://www.ovirt.org/Backend_Coding_Standards .

Change-Id: I94585c734c1cee7e5c29f16604b5d65135cf1061
Signed-off-by: Allon Mureinik <amureini@redhat.com>
core: Singleton row mapper for VdsStatic

Added a singleton row mapper for VdsStaticDAO, as specified by
http://www.ovirt.org/Backend_Coding_Standards .

Change-Id: I43133a64e7c7b62277464326606b376fd4306fbe
Signed-off-by: Allon Mureinik <amureini@redhat.com>
core: Singleton row mapper for vds_spm_id_map

Added a singleton row mapper for VdsSpmIdMapDAO, as specified by
http://www.ovirt.org/Backend_Coding_Standards .

Change-Id: I04b439e9e2868d66f612144dd91e4f65becd9936
Signed-off-by: Allon Mureinik <amureini@redhat.com>
core: LUN_storage_server_connection_map row mapper

Added a singleton row mapper for StorageServerConnectionLunMapDAO, as
specified by http://www.ovirt.org/Backend_Coding_Standards .

Change-Id: Ibd986b67d43c054a98144cde365d6e3f82d82641
Signed-off-by: Allon Mureinik <amureini@redhat.com>