check for ubuntu distribution first

packaging/apt_repository

@@ -349,11 +349,11 @@ def main():
     update_cache = module.params['update_cache']
     sourceslist = None
 
-    if isinstance(distro, aptsources.distro.DebianDistribution) or \
+    if isinstance(distro, aptsources.distro.UbuntuDistribution):
+        sourceslist = UbuntuSourcesList(add_ppa_signing_keys_callback=get_add_ppa_signing_key_callback(module))
+    elif isinstance(distro, aptsources.distro.DebianDistribution) or \
             isinstance(distro, aptsources.distro.Distribution):
         sourceslist = SourcesList()
-    elif isinstance(distro, aptsources.distro.UbuntuDistribution):
-        sourceslist = UbuntuSourcesList(add_ppa_signing_keys_callback=get_add_ppa_signing_key_callback(module))
     else:
         module.fail_json(msg='Module apt_repository supports only Debian and Ubuntu.')