Erik Arvstedt 363b8ff9aa Fix runtime warning when adding log entries
LogEntry.action_time expects a Django timezone object instead of a builtin datetime.

This fixes a runtime warning of the following kind:
RuntimeWarning: DateTimeField LogEntry.action_time received a naive datetime (2018-03-28 20:53:01.714173) while time zone support is active.
2018-03-30 00:15:52 +02:00
..
2017-03-25 16:21:46 +00:00
2018-02-27 13:30:02 +01:00