fruux/sabre-dav — pull request #423 by untitaker (2014-03-19 22:11:00+00:00)
Title: Fix #422

Preconditions weren't checked for PUT requests, although the RFCs specify it
so:

http://tools.ietf.org/search/rfc4791#section-5.3.2

http://tools.ietf.org/html/rfc6352#section-6.3.2