Merge branch 'stable-2.14' into stable-2.15

* stable-2.14:
  Set Gerrit to 2.13.12
  Set Gerrit to 2.14.18
  Set Gerrit to 2.14.17
  Set Gerrit to 2.14.16
  Add support for Gerrit 2.13.11 on ubuntu 14.04 and centos

Change-Id: I79a7f3a9b535440291cbc59d141216516bad7f8f