Fix integer overflow in unpack_sha1_rest()

[jc: later NUL termination by the caller becomes unnecessary]

Signed-off-by: Ilari Liusvaara <ilari.liusvaara@elisanet.fi>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/sha1_file.c b/sha1_file.c
index 63981fb..a903247 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -1232,7 +1232,7 @@
 static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size, const unsigned char *sha1)
 {
 	int bytes = strlen(buffer) + 1;
-	unsigned char *buf = xmalloc(1+size);
+	unsigned char *buf = xmallocz(size);
 	unsigned long n;
 	int status = Z_OK;
 
@@ -1260,7 +1260,6 @@
 		while (status == Z_OK)
 			status = git_inflate(stream, Z_FINISH);
 	}
-	buf[size] = 0;
 	if (status == Z_STREAM_END && !stream->avail_in) {
 		git_inflate_end(stream);
 		return buf;