prefixcmp(): fix-up leftover strncmp().

There were instances of strncmp() that were formatted improperly
(e.g. whitespace around parameter before closing parenthesis)
that caused the earlier mechanical conversion step to miss
them.  This step cleans them up.

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

builtin-rev-parse.c

@@ -233,7 +233,7 @@ int cmd_rev_parse(int argc, const char **argv, const char *prefix)
 			}
 			continue;
 		}
-		if (!strncmp(arg,"-n",2)) {
+		if (!prefixcmp(arg, "-n")) {
 			if ((filter & DO_FLAGS) && (filter & DO_REVS))
 				show(arg);
 			continue;