Tidy up the last regresesions on the python smbscript, from my work

Tidy up the last regresesions on the python smbscript, from my work
with Jelmer today.

The only remaining issue is that for the build farm, we will need to
manually specify the users and groups from the NSS_WRAPPPER, as python
isn't compiled with this.

Andrew Bartlett
(This used to be commit 5370484d25b8c7a5bde730d9be36ecbbb0aaf315)