[ffmpeg] Fix source, it should be tar.xz archive

[Leigh Scott]

commit 8d7697c58e330337ff649fe8fbd16edaaf1a4f78
Author: leigh123linux <leigh123linux at googlemail.com>
Date:   Thu Oct 27 23:06:22 2016 +0100

    Fix source, it should be tar.xz archive

 .gitignore | 1 +
 sources    | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/.gitignore b/.gitignore
index 024b8c7..7c3610a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,3 +5,4 @@ ffmpeg-2.8.7.tar.xz
 /ffmpeg-3.1.4.tar.bz2
 /ffmpeg-3.1.4.tar.xz
 /ffmpeg-3.1.5.tar.bz2
+/ffmpeg-3.1.5.tar.xz
diff --git a/sources b/sources
index bfd1344..e29d051 100644
--- a/sources
+++ b/sources
@@ -1 +1 @@
-0dd2f448a41f555a100fb075d5df136e  ffmpeg-3.1.5.tar.bz2
+a09f7730ceeb665c6f7da0b884dd00f9  ffmpeg-3.1.5.tar.xz