Merge branch 'da/rev-parse-verify-quiet'

"rev-parse --verify --quiet $name" is meant to quietly exit with a
non-zero status when $name is not a valid object name, but still
gave error messages in some cases.

* da/rev-parse-verify-quiet:
  stash: prefer --quiet over shell redirection of the standard error stream
  refs: make rev-parse --quiet actually quiet
  t1503: use test_must_be_empty
  Documentation: a note about stdout for git rev-parse --verify --quiet

refs.h

@@ -206,7 +206,8 @@ extern int write_ref_sha1(struct ref_lock *lock, const unsigned char *sha1, cons
 int log_ref_setup(const char *refname, char *logfile, int bufsize);
 
 /** Reads log for the value of ref during at_time. **/
-extern int read_ref_at(const char *refname, unsigned long at_time, int cnt,
+extern int read_ref_at(const char *refname, unsigned int flags,
+		       unsigned long at_time, int cnt,
 		       unsigned char *sha1, char **msg,
 		       unsigned long *cutoff_time, int *cutoff_tz, int *cutoff_cnt);