appdata: Use system-config-printer.desktop as id (fixes #273)

Although it is against appstream policy, but `appstream-util validate`
passes and the app can be uninstalled via GNOME Software - let's start
using system-config-printer.desktop as id until a better solution is
found.

Author: zdohnal

NEWS

@@ -1,6 +1,7 @@
 1.5.18 changes
 --------------
 - Add <launchable/> into the .appdata.xml file (#269)
+- system-config-printer couldn't be uninstalled vi GNOME Software (#273)
 
 1.5.17 changes
 --------------

system-config-printer.appdata.xml.in

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <component type="desktop">
-  <id>org.fedoraproject.systemconfigprinter</id>
+  <id>system-config-printer.desktop</id>
   <metadata_license>CC0</metadata_license>
   <project_license>GPL-2.0+</project_license>
   <name>Print Settings</name>