Mount /etc/yum.repos.d from host to storage-repo

We have to mount /etc/yum.repos.d into fuel-storage-repo container if we
want to get latest repos inside containers. Otherwise we will have
latest repos, but they won't be used.

Change-Id: I66178d44ed667e56293093d9c91c71c540a86069
Closes-Bug: #1390375

(cherry picked from commit f43179a544b2e8a628c7fff99d20daf603cdfa47)

Change-Id: I93e227ebbd99906a246b58b602f84d088e4f79ec