sync.desktop: fixed "make dist" after recent rename

The file which has to be distributed is "sync.desktop.in" now,
not "sync.desktop".

.gitignore

@@ -15,5 +15,8 @@ ltmain.sh
 missing
 Makefile.in
 src/Makefile.am
+po/Makefile.in.in
+mkinstalldirs
+intltool-*.in
 .gitignore
 *.patch

src/gtk-ui/Makefile.am

@@ -14,13 +14,11 @@ themerc_DATA = \
 	sync-ui.rc
 
 desktopdir = $(datadir)/applications
-desktop_DATA = \
-	sync.desktop
 
 EXTRA_DIST = \
 	ui.glade \
 	$(themerc_DATA) \
-	$(desktop_DATA) \
+	$(applications_in_files) \
 	$(noinst_DATA)
 
 ui.xml: ui.glade