samba-tool: Use samba.glue.get_burnt_cmdline rather than regex

samba-tool: Use samba.glue.get_burnt_cmdline rather than regex

This use avoids having two different methods to match on command-line
passwords.  We already have a dependency on the setproctitle python
module, and this does not change as the (C) libbsd setproctitle()
can't be run from within a python module.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15289

Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>