Convert memset(hash,0,20) to hashclr(hash).

In the same spirit as hashcmp() and hashcpy().

Signed-off-by: Junio C Hamano <junkio@cox.net>

blame.c

@@ -165,7 +165,7 @@ static int get_blob_sha1(struct tree *t, const char *pathname,
 	blame_file = pathname;
 	pathspec[0] = pathname;
 	pathspec[1] = NULL;
-	memset(blob_sha1, 0, sizeof(blob_sha1));
+	hashclr(blob_sha1);
 	read_tree_recursive(t, "", 0, 0, pathspec, get_blob_sha1_internal);
 
 	for (i = 0; i < 20; i++) {

builtin-update-ref.c

@@ -44,7 +44,7 @@ int cmd_update_ref(int argc, const char **argv, const char *prefix)
 
 	if (get_sha1(value, sha1))
 		die("%s: not a valid SHA1", value);
-	memset(oldsha1, 0, 20);
+	hashclr(oldsha1);
 	if (oldval && get_sha1(oldval, oldsha1))
 		die("%s: not a valid old SHA1", oldval);
 

cache.h

@@ -222,6 +222,10 @@ static inline void hashcpy(unsigned char *sha_dst, const unsigned char *sha_src)
 {
 	memcpy(sha_dst, sha_src, 20);
 }
+static inline void hashclr(unsigned char *hash)
+{
+	memset(hash, 0, 20);
+}
 
 int git_mkstemp(char *path, size_t n, const char *template);
 

diff-lib.c

@@ -48,7 +48,7 @@ int run_diff_files(struct rev_info *revs, int silent_on_removed)
 			memcpy(dpath->path, ce->name, path_len);
 			dpath->path[path_len] = '\0';
 			dpath->mode = 0;
-			memset(dpath->sha1, 0, 20);
+			hashclr(dpath->sha1);
 			memset(&(dpath->parent[0]), 0,
 					sizeof(struct combine_diff_parent)*5);
 

http-push.c

@@ -2164,7 +2164,7 @@ static void fetch_symref(const char *path, char **symref, unsigned char *sha1)
 	if (*symref != NULL)
 		free(*symref);
 	*symref = NULL;
-	memset(sha1, 0, 20);
+	hashclr(sha1);
 
 	if (buffer.posn == 0)
 		return;

sha1_name.c

@@ -159,7 +159,7 @@ static int get_short_sha1(const char *name, int len, unsigned char *sha1,
 
 	if (len < MINIMUM_ABBREV)
 		return -1;
-	memset(res, 0, 20);
+	hashclr(res);
 	memset(canonical, 'x', 40);
 	for (i = 0; i < len ;i++) {
 		unsigned char c = name[i];