[frogr] Fix 'make distcheck' (intltool bug with separate build dirs)

[Mario Sanchez Prada <msanchez src gnome org>]

commit 32db6d05f0b511d25850adca14ce54f80c3df7ef
Author: Mario Sanchez Prada <msanchez gnome org>
Date:   Wed Dec 30 01:35:18 2015 +0000

    Fix 'make distcheck' (intltool bug with separate build dirs)
    
    For now we will just add the sub/ subdirectory to the POTFILES.skip
    file. More info in https://bugs.launchpad.net/intltool/+bug/1117944.

 po/POTFILES.skip |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)
---
diff --git a/po/POTFILES.skip b/po/POTFILES.skip
index 5e66c6b..56f1fab 100644
--- a/po/POTFILES.skip
+++ b/po/POTFILES.skip
@@ -1 +1,6 @@
 data/frogr.desktop.in
+
+# We need to explicitly skip this file or make distcheck will fail due to
+# a bug in intltool (see https://bugs.launchpad.net/intltool/+bug/1117944).
+sub/data/frogr.desktop.in
+