1. Fix#5102 by checking the existence of name when creating/editing replication rule
2. Add unique constraint to the name of replication policy and target
3. Fix bugs of testing library
Signed-off-by: Wenkai Yin <yinw@vmware.com>
Move admin_client to testutil.py as global parameter.
Change create_repository function name to push_image_to_project to make it reasonable.
Signed-off-by: danfengliu <danfengl@vmware.com>