Changes needed for testing privileges on Travis-CI.

 * pyrseas/dbobject/foreign.py (ForeignDataWrapperDict.from_map): Use
   sorted list of input wrapper keys, so that 'owner' comes before
   'privileges'.
 * tests/dbobject/test_privs.py
   (PrivilegeToSqlTestCase.test_table_change_grant): Verify statements
   against a sorted list because they depend on the database owner
   name.