selftest: Designate one testenv as having SMBv1 disabled

selftest: Designate one testenv as having SMBv1 disabled

We recommend users disable SMBv1 to avoid potential security holes.
However, none of the AD DC testenvs have SMBv1 disabled.

This patch disables SMBv1 on an arbitrarily-chosen testenv (restoredc).

I chose restoredc as we'll want to run the backup tool tests against
this target, and it might be useful to check we can backup a DC if it's
already been restored once.

Note that SMBv2 doesn't support POSIX extensions (only SMBv1 does),
which is why we haven't just disabled SMBv1 on *all* testenvs.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=13676

Signed-off-by: Tim Beale <timbeale@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>