make clean in valgrind_test.sh first

Summary: some changes require make clean to be done before make. auto_roll_Logger_test was failing on valgrind possibly due to this.

Test Plan: valgrind ./auto_roll_logger_test

Reviewers: sheki

Reviewed By: sheki

Differential Revision: https://reviews.facebook.net/D10509

valgrind_test.sh

@@ -3,6 +3,7 @@
 #Returns 0 on success when there are no failed tests 
 
 VALGRIND_DIR=VALGRIND_LOGS
+make clean
 make -j$(nproc) valgrind_check
 NUM_FAILED_TESTS=$((`wc -l $VALGRIND_DIR/valgrind_failed_tests | awk '{print $1}'` - 1))
 if [ $NUM_FAILED_TESTS -lt 1 ]; then