moar plusses!

turns out that 0.34.1.1+1 comes before 0.34.1.1+bionic (etc).

The version may only contain "~ 0-9 A-Z a-z + - ." (sorting in that order).

Option 1: replace "+" with something that sorts after +. Options are "-" (but
dpkg-source complains about that) or "." (but that would mean we couldn't
distinguish packaging-only changes from real changes).

Option 2: stick with + and just find something that sorts after 'xenial'. The
only options there are "-", "." (same problems as before), "z", and "+".

Hence, ++1. Sorry.

debian/changelog

@@ -1,8 +1,8 @@
-matrix-synapse-py3 (0.34.1.1+1) UNRELEASED; urgency=medium
+matrix-synapse-py3 (0.34.1.1++1) stable; urgency=medium
 
   * Update conflicts specifications to allow smoother transition from matrix-synapse.
 
- -- Synapse Packaging team <packages@matrix.org>  Fri, 11 Jan 2019 17:04:28 +0000
+ -- Synapse Packaging team <packages@matrix.org>  Sat, 12 Jan 2019 12:58:35 +0000
 
 matrix-synapse-py3 (0.34.1.1) stable; urgency=high