XenAPI: Fix race condition on tailing stack.log

Stack.log is created by stack.sh, which is started by run.sh.  Using
the pid from run.sh doesn't mean that stack.log has been created yet
so wait for the log to be created before tailing

Change-Id: I86e563478949cb7bbe0d1afd80b790ba70328e3a
Fix default_volume_type for Cinder multi backend

The default_volume_type option doesn't support comma separated
arguments. We can only select one default volume type.
We have a variable that contains the default volume type, so we simply use it.

Closes-Bug: 1342569

Change-Id: Ibd080442f00f3d446ec374fc5906f0778d449007
Signed-off-by: Sébastien Han <sebastien.han@enovance.com>
Add WSGISocketPrefix to apache keystone config

I think since probably fdf1cffbd5d2a7b47d5bdadbc0755fcb2ff6d52f
devstack on RHEL6 fails and it comes down to:

---
2014-07-17 05:05:49.235 | +++ openstack role create admin -f value -c id
2014-07-17 05:05:49.615 | ERROR: cliff.app Service Unavailable (HTTP 503)

[Thu Jul 17 15:05:46 2014] [error] [client 10.0.2.15]
  (13)Permission denied: mod_wsgi (pid=30125): Unable to connect to WSGI
   daemon process 'keystone-public' on
   '/etc/httpd/logs/wsgi.30098.0.1.sock' after multiple attempts.
---

The apache user doesn't have permissons to this directory.  Adding
WSGISocketPath to /var/run solves it

Change-Id: If4b74019b6bd389b576fc981154bb1b3aa471c9b
Merge "Add WSGISocketPrefix to apache keystone config"
Merge "XenAPI: Fix race condition on tailing stack.log"
Merge "Fix default_volume_type for Cinder multi backend"