Add ldb_test.py back to make check

Summary: This is revert of D40449. I'm not sure why our tests failed before, they seem to be working fine on my devbox.

Test Plan: ran `make check`

Reviewers: anthony

Reviewed By: anthony

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D41955

Makefile

@@ -519,6 +519,7 @@ check: all
 	      echo "===== Running $$t"; ./$$t || exit 1; done;          \
 	fi
 	rm -rf $(TMPD)
+	python tools/ldb_test.py
 	sh tools/rocksdb_dump_test.sh
 
 check_some: $(SUBSET) ldb_tests