do not do utf-8 twice; make sure before_/after_time/name possible newlines are taken into account in history window too

src/conversation_textview.py

@@ -711,7 +711,6 @@ class ConversationTextview:
 			# if tim_format comes as unicode because of day_str.
 			# we convert it to the encoding that we want (and that is utf-8)
 			tim_format = helpers.ensure_utf8_string(tim_format)
-			tim_format = tim_format.encode('utf-8')
 			buffer.insert_with_tags_by_name(end_iter, tim_format + ' ',
 				*other_tags_for_time)
 		elif current_print_time == 'sometimes' and kind != 'info':

src/history_window.py

@@ -210,7 +210,9 @@ class HistoryWindow:
 		
 		if gajim.config.get('print_time') == 'always':
 			before_str = gajim.config.get('before_time')
+			before_str = helpers.from_one_line(before_str)
 			after_str = gajim.config.get('after_time')
+			after_str = helpers.from_one_line(after_str)
 			format = before_str + '%X' + after_str + ' '
 			tim = time.strftime(format, time.localtime(float(tim)))
 			buf.insert(end_iter, tim) # add time