partial fix for renegotiating pm e2e sessions after one party

disconnects

src/chat_control.py

@@ -2583,7 +2583,7 @@ class ChatControl(ChatControlBase):
 
 		if not self.session:
 			fjid = self.contact.get_full_jid()
-			new_sess = gajim.connections[self.account].make_new_session(fjid)
+			new_sess = gajim.connections[self.account].make_new_session(fjid, type_=self.type_id)
 			self.set_session(new_sess)
 
 		self.session.negotiate_e2e(False)

src/common/connection_handlers.py

@@ -1350,6 +1350,8 @@ sent a message to.'''
 			return None
 
 	def make_new_session(self, jid, thread_id=None, type_='chat', cls=None):
+		'''create and register a new session. thread_id=None to generate one.
+		type_ should be 'chat' or 'pm'.'''
 		if not cls:
 			cls = gajim.default_session_type