shortlog: remove "[PATCH]" prefix from shortlog output

Originally noticed by Nicolas Pitre; the real cause was the code
was prepared to deal with [PATCH] (and [PATCH n/m whatever])
prefixes but forgot that the string can be indented while acting
as a filter.

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

builtin-shortlog.c

@@ -195,11 +195,17 @@ static void read_from_stdin(struct path_list *list)
 			while (fgets(buffer2, sizeof(buffer2), stdin) &&
 					buffer2[0] != '\n')
 				; /* chomp input */
-			if (fgets(buffer2, sizeof(buffer2), stdin))
+			if (fgets(buffer2, sizeof(buffer2), stdin)) {
+				int l2 = strlen(buffer2);
+				int i;
+				for (i = 0; i < l2; i++)
+					if (!isspace(buffer2[i]))
+						break;
 				insert_author_oneline(list,
 						buffer + offset,
 						bob - buffer - offset,
-						buffer2, strlen(buffer2));
+						buffer2 + i, l2 - i);
+			}
 		}
 	}
 }