builtin/apply: free patch when parse_chunk() fails

When parse_chunk() fails it can return -1, for example
when find_header() doesn't find a patch header.

In this case it's better in apply_patch() to free the
"struct patch" that we just allocated instead of
leaking it.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/apply.c

@@ -4371,8 +4371,10 @@ static int apply_patch(int fd, const char *filename, int options)
 		patch->inaccurate_eof = !!(options & INACCURATE_EOF);
 		patch->recount =  !!(options & RECOUNT);
 		nr = parse_chunk(buf.buf + offset, buf.len - offset, patch);
-		if (nr < 0)
+		if (nr < 0) {
+			free_patch(patch);
 			break;
+		}
 		if (apply_in_reverse)
 			reverse_patches(patch);
 		if (use_patch(patch)) {