eventscript: use wire format internally for script status.

eventscript: use wire format internally for script status.

The only difference between the exposed an internal structure now is
that the name and output fields were pointers.  Switch to using
ctdb_scripts_wire/ctdb_script_wire internally as well so marshalling
is a noop.

We now reject scripts which are too long and truncate logging to the
511 characters we have space for (the entire output will be in the
normal ctdbd log).

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>