Add an error to mpi emcee abort

This does not really do what we want, but hoefully it stops all jobs

src/fitting/ensemble-samplers/emcee.sl

@@ -1658,6 +1658,7 @@ private define emceeMPIAbort (ship) %{{{
 #ifexists rcl_mpi_abort
   rcl_mpi_abort(1); % hopefully 0 is allway success
 #endif
+  throw InternalError;
 }
 %}}}
 %}}}