* src/security_selinux.c: ignores EOPNOTSUPP when attempting to access an
  NFS share

* src/security_selinux.c: Skip relabelling of shared/readonly
  disks upon shutdown, since this breaks other VMs still active
  using those disks

Fixes startup of guest's with sourceless cdrom devices.

Patch from Cole Robinson originally posted here:

  https://bugzilla.redhat.com/499569

but never sent upstream.
Signed-off-by: NMark McLoughlin <markmc@redhat.com>

As pointed out by Tim Waugh here:

  https://bugzilla.redhat.com/507555

We shouldn't bother trying to set the context of a file if it already
matches what we want.

(Fixed to use STREQ() and not use tabs, as pointed out by danpb)
Signed-off-by: NMark McLoughlin <markmc@redhat.com>

This patch was posted ages ago here:

  https://bugzilla.redhat.com/493692

But was never posted upstream AFAICT.

Patch from Dan Berrange
Signed-off-by: NMark McLoughlin <markmc@redhat.com>