Fix bug introduced in a8709c0e

The missing comma would cause site.images[filename] to fail

mwclient/page.py

@@ -382,7 +382,7 @@ class Image(Page):
         site.require(1, 11)
         Page.__init__(self, site, name, info,
                       extra_properties={'imageinfo':
-                                        (('iiprop', 'timestamp|user|comment|url|size|sha1|metadata|archivename'))
+                                        (('iiprop', 'timestamp|user|comment|url|size|sha1|metadata|archivename'), )
                                         })
         self.imagerepository = self._info.get('imagerepository', '')
         self.imageinfo = self._info.get('imageinfo', ({}, ))[0]