Removed extension from icon name in desktop file. This relates to bug

2424.

Signed-off-by: Michele Calgaro <michele.calgaro@yahoo.it>

data/desktop/x-rosegarden.desktop

@@ -2,7 +2,7 @@
 Comment=Rosegarden file
 Comment[fr]=Fichier Rosegarden
 Hidden=false
-Icon=x-rosegarden.png
+Icon=x-rosegarden
 MimeType=audio/x-rosegarden
 Patterns=*.rg;*.RG
 Type=MimeType