core, plugins: host.getClient now raise an exception instead of returning None when no profile is found, plugins have been adapted consequently and a bit cleaned

src/plugins/plugin_xep_0054.py

@@ -259,8 +259,6 @@ class XEP_0054(object):
         #TODO: This is a temporary way of setting avatar, as other VCard informations are not managed.
         #      A proper full VCard management should be done (and more generaly a public/private profile)
         client = self.host.getClient(profile_key)
-        if not client:
-            raise exceptions.NotConnectedProfileError(_('Trying to set avatar for a non-existant or not connected profile'))
 
         vcard_set = IQ(client.xmlstream, 'set')
         d = threads.deferToThread(self._buildSetAvatar, vcard_set, filepath)