net-im/gajim: update to 0.16.7

Gajim 0.16.7 (30 January 2017)

• Better compatibility with XEP-0191: Blocking Command
• Windows Credential Vault is used for password storage on Windows
• Gajim now depends on python-gnupg for PGP encryption
• Add portable installer for Windows
• Remove usage of demandimport
• Many minor bugfixes