Fix again the test code of testUpdateWithPGobject

Fix the ResultSet cannot be updated by initialize statement with
flag "CONCUR_UPDATABLE"

Set primary key for test table "testpgobject" to resolve
"No primary key" issue when trying to update the table
Merge pull request #233 from kingter/fix_testUpdateWithPGobject_resultset

Fix the test code of testUpdateWithPGobject, for cannot update ResultSet