Comment 5 for bug 1538335

Reviewed: https://review.openstack.org/274055
Committed: https://git.openstack.org/cgit/openstack/fuel-main/commit/?id=94507c5e4dad6d8cfbd8f5d41aa8389d5335990a
Submitter: Jenkins
Branch: stable/8.0

commit 94507c5e4dad6d8cfbd8f5d41aa8389d5335990a
Author: Dmitry Teselkin <email address hidden>
Date: Thu Jan 28 00:43:40 2016 +0300

    Fix USB installation

    The follwing errors during installation from USB stick/image
    caused by the attempt to mount partition that already used

      + mount /dev/disk/by-label/Mirantis_Fuel /tmp/source
      mount: /dev/sda1 is write-protected, mounting read-only
      mount: /dev/sda1 is already mounted or /tmp/source busy

    Anaconda mounts paritions from 'repo' automatically (not sure
    about nfs partitions but there is a code to mount is explicitely),
    so it's not possible to re-mount it. However, we can mount it
    with 'bind' option to make avaible in another path.

    This commit collects all the logic to mount SOURCE path
    in one place and adds additional checks to avoid mointing when
    SOURCE path set up already.

    Change-Id: Idd7f56f23a8bab604d78f2b83f0290e8006482dc
    Closes-bug: #1538335
    (cherry picked from commit c2bae141ba2c08a1c5c9416cf941f27043c609ea)