output/lua: better lua output setup error handling

output/lua: better lua output setup error handling

If suricata was started with --init-errors-fatal and an error occured
during setup of lua output (like if lua scripts configured in the conf file
don't exist or are not readable) suricata continued, which did not reflect
"init errors fatal" very well.

This fix makes the suricata initialization abort and send an error message
in such cases.

For details see:
https://redmine.openinfosecfoundation.org/issues/1503