If the Storage Pool Namespace XML data exists, format the mount
options on the MOUNT command line and issue a VIR_WARN to indicate
that the storage pool was tainted by custom mount_opts.

When the pool is started, the options will be generated on the
command line along with the options already defined.
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>
Reviewed-by: NDaniel P. Berrangé <berrange@redhat.com>

https://bugzilla.redhat.com/show_bug.cgi?id=1584663

Modify the command generation to add some default options to the
fs/netfs storage pools based on the OS type. For Linux, it'll be
the "nodev, nosuid, noexec". For FreeBSD, it'll be "nosuid, noexec".
For others, just leave the options alone.

Modify the storagepoolxml2argvtest to handle the fact that the
same input XML could generate different output XML based on whether
Linux, FreeBSD, or other was being built.
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>
Reviewed-by: NDaniel P. Berrangé <berrange@redhat.com>