Modify default repos for fuel and fuelmenu

[OpenStack Infra]

https://review.openstack.org/419563
Dear bug triager. This bug was created since a commit was marked with DOCIMPACT.

commit 363fff0cf0a749614a4c29bd1036b1711586dad1
Author: Vladimir Kozhukalov <email address hidden>
Date: Thu May 26 08:15:17 2016 +0300

    Modify default repos for fuel and fuelmenu

    In fuel (nailgun) and fuelmenu we have hardcoded
    default repos which we should be able to change
    mostly for test purposes.

    Default ISO build flow uses fuel packages rebuild
    approach, which modifies ubuntu suit as well, eg:
       sync(mos-master) --> (iso)mos10.0 --> deploy(mos10.0)

    To use this feature one must use BUILD_PACKAGES=0,
    this flag turns off:
      * fuel packages building and
      * ubuntu suit update.
    so We consume the same suit as we use during
    debmirroring, eg:
       sync(mos-master) --> iso(mos-master) --> deploy(mos-master)

    DocImpact
    Change-Id: Ia3cefa7c87e35ecd9244a4026b86e772bf569ca9
    Closes-bug: #1556125
    (cherry picked from commit e6b165748a8771a9f15d3416fc0cd05b6e40b63a)