Adjust the Thrift compiler makefile to clean up after the obj/ folder that it builds into

Summary: I am super nitpicky, and after make clean I don't like seeing:
$ svn st
?   obj/

Problem: make clean didn't remove the generated obj/ dir

Solution: Kill it!

Reviewed By: aditya

Test Plan: Do make clean in compiler directory followed by svn st. You should see nothing!





git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@664717 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/compiler/Makefile b/compiler/Makefile
index 49833cb..938ef50 100644
--- a/compiler/Makefile
+++ b/compiler/Makefile
@@ -96,9 +96,8 @@
 
 # Remove auto-gen'd files and binaries
 clean:
-	rm -f \
-	$(OBJS) \
-	$(GOBS) \
+	rm -fr \
+	$(OBJ_DIR) \
 	$(GENS) \
 	$(BIN_DIR)thrift.exe \
 	$(BIN_DIR)thrift