use xstrncmpz()

Add and apply a semantic patch for calling xstrncmpz() to compare a
NUL-terminated string with a buffer of a known length instead of using
strncmp() and checking the terminating NUL explicitly.  This simplifies
callers by reducing code duplication.

I had to adjust remote.c manually because Coccinelle inexplicably
changed the indent of the else branches.

Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

object.c

@@ -47,8 +47,7 @@ int type_from_string_gently(const char *str, ssize_t len, int gentle)
 		len = strlen(str);
 
 	for (i = 1; i < ARRAY_SIZE(object_type_strings); i++)
-		if (!strncmp(str, object_type_strings[i], len) &&
-		    object_type_strings[i][len] == '\0')
+		if (!xstrncmpz(object_type_strings[i], str, len))
 			return i;
 
 	if (gentle)