dal: Remove duplicate fields in VM row mappers

Removed duplicate fields that were specified both in AbstractVmRowMapper
and its descendants VmStaticRowMapper and VmTemplateRowMapper.

Also extracted fields found in both children back to
AbstractVmRowMapper.

Change-Id: Iab2a3bf9a0deb25b3950f75a351bde4b9e6fef74
Signed-off-by: Martin Betak <mbetak@redhat.com>