MINOR: lua: Slightly improve function dumping the lua traceback

The separator string is now configurable, passing it as parameter when the
function is called. In addition, the message have been slightly changed to
be a bit more readable.

(cherry picked from commit d09cc519bd0c04a0d1ec5bf23ed053c1e596851a)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
2 files changed