update electrum package

Opened #9713 (closed) which was rejected with the comment to reopen when package is updated upstream.

Won’t describe again the problems related to the older version, but see:
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=792231

We should update with our next Tails release (wheezy/jessie).

Original created by @s7r on 10073 (Redmine)

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information