Improve debuggability when call-count numbers don't match up

Conflicts:
	common/lib/xmodule/xmodule/modulestore/tests/factories.py
	common/lib/xmodule/xmodule/modulestore/tests/test_mixed_modulestore.py
Add test to verify bad query behavior of xblock_handler
fixup! Add test to verify bad query behavior of xblock_handler
Update Cale's mongo tests with the new numbers