[ixpmanager] New release - v3.6.15 - Per LAG Aggregates

[Barry O'Donovan]

https://github.com/inex/IXP-Manager/releases/tag/v3.6.15

The primary feature of this release is the addition of per LAG aggregate 
graphs (where previously we only had per port and a single aggregate for 
all ports).


You can upgrade directly from 3.6.13 to 3.6.15.


UPGRADING
==============

Please follow the instructions carefully and do not miss any steps:

https://github.com/inex/IXP-Manager/wiki/Installation-09-Upgrading-IXP-Manager

  - Barry