Log Message:
Update Radicale2 to 2.1.5

2.1.5 - Wild Radish
-------------------

This release is compatible with version 2.0.0.

* Add ``--verify-storage`` command-line argument
* Allow comments in the htpasswd file
* Don't strip whitespaces from user names and passwords in the htpasswd file
* Remove cookies from logging output
* Allow uploads of whole collections with many components
* Show warning message if server.timeout is used with Python < 3.5.2