usr.bin/calendar: re-sync with upstream.

Jenkins was failing on usr.bin/calendar/calendar.c:386:6: with
"error: 'fd' may be used uninitialized in this function"
when the level of error checking was turned up.

The error was recently fixed upstream. This commit updates
calendar.c to upstream rev 1.50, updates calendar files too.

Change-Id: Ibe0695bf5d0315972f2a4fb1175219dd12cbfa5a