"make commit-prereq" doesn't really build ROCKSDB_LITE

Summary: "make commit-prereq" uses "make release" which overrides OPT, so ROCKSDB_LITE is not covered. Fix it by using "make static_lib"

Test Plan: Run it and see it fail (which is expected)

Reviewers: yhchiang, meyering, rven, anthony, kradhakrishnan, igor

Reviewed By: igor

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D36813

Makefile

@@ -921,7 +921,7 @@ commit-prereq:
 	$(MAKE) clean && $(MAKE) all check;
 	$(MAKE) clean && $(MAKE) rocksdbjava;
 	$(MAKE) clean && USE_CLANG=1 $(MAKE) all;
-	$(MAKE) clean && OPT=-DROCKSDB_LITE $(MAKE) release;
+	$(MAKE) clean && OPT=-DROCKSDB_LITE $(MAKE) static_lib;
 
 # ---------------------------------------------------------------------------
 #  	Platform-specific compilation