fix the bug of configure.

@@ -315,7 +315,7 @@ help:
 
 clean: 
 	(cd ${SRS_OBJS_DIR}; rm -rf srs srs_utest $__mcleanups)
-	(cd ${SRS_OBJS_DIR}; rm -rf src research include lib)
+	(cd ${SRS_OBJS_DIR}; rm -rf src include lib)
 	(cd ${SRS_OBJS_DIR}/utest; rm -rf *.o *.a)
 	(cd research/librtmp; make clean)
 	(cd research/api-server/static-dir; rm -rf crossdomain.xml forward live players)