Removed unused imports - should have been in the last commit obviously

Author: Byron

gitdb/test/db/test_git.py

@@ -5,7 +5,6 @@
 import os
 from gitdb.test.db.lib import (
     TestDBBase,
-    fixture_path,
     with_rw_directory
 )
 from gitdb.exc import BadObject

gitdb/test/db/test_ref.py

@@ -5,7 +5,6 @@
 from gitdb.test.db.lib import (
     TestDBBase,
     with_rw_directory,
-    fixture_path
 )
 from gitdb.db import ReferenceDB