Currently, we install python-rados and python-rbd via apt when ceph
integration is enabled, which causes issues when venvs are used in the
environment. This commit adds a temporary work-around by creating
symlinks in the venv to the installed libraries outside.
There is currently a ceph issue [1] in progress to make this possible,
and once this has been completed we can update ceph_client role to
install python packages instead.
[1] http://tracker.ceph.com/issues/5900
Change-Id: Ia7a3ceae002054fd75e0305892b20ce1143f8dcc
Closes-Bug: #1509837