Minor restructuring/clarification to get_backup_name.

(Tweaked by Wayne to follow his preferred style.)

backup.c

@@ -160,13 +160,13 @@ char *get_backup_name(const char *fname)
 		/* copy fname into backup_dir_buf while validating the dirs. */
 		if (copy_valid_path(fname))
 			return backup_dir_buf;
+		/* copy_valid_path() has printed an error message. */
 		return NULL;
-	} else {
-		if (stringjoin(backup_dir_buf, MAXPATHLEN,
-			       fname, backup_suffix, NULL) < MAXPATHLEN)
-			return backup_dir_buf;
 	}
 
+	if (stringjoin(backup_dir_buf, MAXPATHLEN, fname, backup_suffix, NULL) < MAXPATHLEN)
+		return backup_dir_buf;
+
 	rprintf(FERROR, "backup filename too long\n");
 	return NULL;
 }