refs.c: let fprintf handle the formatting

Instead of calculating whether to put a plus or minus sign, offload
the responsibilty to the fprintf function.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

refs.c

@@ -3972,12 +3972,9 @@ static int expire_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
 			printf("prune %s", message);
 	} else {
 		if (cb->newlog) {
-			char sign = (tz < 0) ? '-' : '+';
-			int zone = (tz < 0) ? (-tz) : tz;
-			fprintf(cb->newlog, "%s %s %s %lu %c%04d\t%s",
+			fprintf(cb->newlog, "%s %s %s %lu %+05d\t%s",
 				sha1_to_hex(osha1), sha1_to_hex(nsha1),
-				email, timestamp, sign, zone,
-				message);
+				email, timestamp, tz, message);
 			hashcpy(cb->last_kept_sha1, nsha1);
 		}
 		if (cb->flags & EXPIRE_REFLOGS_VERBOSE)