refs.c: make lock_ref_sha1 static

No external callers reference lock_ref_sha1 any more so let's declare it
static.

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

refs.c

@@ -2069,7 +2069,10 @@ int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
 	return logs_found;
 }
 
-/* This function should make sure errno is meaningful on error */
+/*
+ * Locks a "refs/" ref returning the lock on success and NULL on failure.
+ * On failure errno is set to something meaningful.
+ */
 static struct ref_lock *lock_ref_sha1_basic(const char *refname,
 					    const unsigned char *old_sha1,
 					    int flags, int *type_p)
@@ -2170,7 +2173,7 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
 	return NULL;
 }
 
-struct ref_lock *lock_ref_sha1(const char *refname, const unsigned char *old_sha1)
+static struct ref_lock *lock_ref_sha1(const char *refname, const unsigned char *old_sha1)
 {
 	char refpath[PATH_MAX];
 	if (check_refname_format(refname, 0))

refs.h

@@ -170,12 +170,6 @@ extern int ref_exists(const char *);
  */
 extern int peel_ref(const char *refname, unsigned char *sha1);
 
-/*
- * Locks a "refs/" ref returning the lock on success and NULL on failure.
- * On failure errno is set to something meaningful.
- */
-extern struct ref_lock *lock_ref_sha1(const char *refname, const unsigned char *old_sha1);
-
 /** Locks any ref (for 'HEAD' type refs). */
 #define REF_NODEREF	0x01
 /* errno is set to something meaningful on failure */