selftest: Remove unnecessary tests.py options from proclimit tests

selftest: Remove unnecessary tests.py options from proclimit tests

It seems like these extra options were just copy-n-pasted from another
test. The process_limits test doesn't actually try to use these env
variables at all. All the test is doing is creating LDAP connections to
the DC. The SOCKET_WRAPPER_DEFAULT_IFACE may have perhaps been needed,
but we can avoid this by dropping ':local' from the testenv and running
the test as a "client" instead.

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