samba-log-parser: make python optional

samba-log-parser: make python optional

Forwarded: not-needed
Debian-Specific: yes

samba-log-parser is a rarely used utility written in python.
It is the only python program in the samba-common-bin package.
By using this simple trick (wrapping the script into #!/bin/sh)
we can make the python package optional, to be able to install
minimal samba client.

Gbp-Pq: Name make-python-optional.diff