qemu_process: Produce better debug message wrt domain namespaces

qemu_process: Produce better debug message wrt domain namespaces

When going through debug log of a domain startup process, one can
meet the following line:

  debug : qemuProcessLaunch:7668 : Building mount namespace

But this is in fact wrong. Firstly, domain namespaces are just
enabled in domain's privateData. Secondly, the debug message says
nothing about actual state of namespace - whether it was enabled
or not.

Therefore, move the debug printing into
qemuProcessEnableDomainNamespaces() and tweak it so that the
actual value is reflected.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Jim Fehlig <jfehlig@suse.com>