calcurse-caldav: drop misplaced filter argument

We cannot use the filter options when importing events.

This was noticed because the new calcurse argument parser catches
invalid input flag combinations and bails out.

Partly addresses GitHub issue #177.

Signed-off-by: Lukas Fleischer <lfleischer@calcurse.org>

contrib/caldav/calcurse-caldav.py

@@ -69,7 +69,6 @@ def calcurse_import(icaldata):
         '-i', '-',
         '--dump-imported',
         '-q',
-        '--filter-type', sync_filter,
         '--format-apt=%(hash)\\n',
         '--format-recur-apt=%(hash)\\n',
         '--format-event=%(hash)\\n',