[gnome-nibbles] appdata: update license metadata

[Michael Catanzaro <mcatanzaro src gnome org>]

commit a8b77e725f86aef5dc30581c26ab5f07bdfd8faf
Author: Michael Catanzaro <mcatanzaro gnome org>
Date:   Sun May 11 11:22:51 2014 -0500

    appdata: update license metadata

 data/gnome-nibbles.appdata.xml.in |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/data/gnome-nibbles.appdata.xml.in b/data/gnome-nibbles.appdata.xml.in
index 23cf6e8..f56373b 100644
--- a/data/gnome-nibbles.appdata.xml.in
+++ b/data/gnome-nibbles.appdata.xml.in
@@ -2,7 +2,8 @@
 <!-- Copyright 2013 Michael Catanzaro -->
 <application>
  <id type="desktop">gnome-nibbles.desktop</id>
- <licence>CC0</licence>
+ <metadata_licence>CC0-1.0</metadata_licence>
+ <project_license>GPL-2.0+ and CC-BY-SA-3.0</project_license>
  <_name>GNOME Nibbles</_name>
  <description>
   <_p>