core: Remove methods concerning pool types from storage dao

As a part of the effort to remove the type of storage pool the unused
methods concerning pool types were removed in StorageDomainStaticDao and
their tests

Relates-To: https://bugzilla.redhat.com/1038053
Change-Id: Iab29347dd82ea47bf6e0d1d5542db9d6d52c0b08
Signed-off-by: Tal Nisan <tnisan@redhat.com>