srcctl3: Improve debug messages

srcctl3: Improve debug messages

A customer's syslog was filled with

_svcctl_OpenServiceW: Failed to get a valid security descriptor

messages. This improves the messages to give info about which service failed
with which error code. Also, it makes OpenServiceW fail with the same error
message Windows fails with for unknown services.

Signed-off-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
Autobuild-User(master): Jeremy Allison <jra@samba.org>
Autobuild-Date(master): Tue Jan 16 02:43:03 CET 2018 on sn-devel-144