don't generate scheduling information without -write-scheduling-data

Link: https://github.com/sebhtml/ray/issues/190
Signed-off-by: Sébastien Boisvert <sebastien.boisvert.3@ulaval.ca>
add option -write-plugin-data to write plugin data

Signed-off-by: Sébastien Boisvert <sebastien.boisvert.3@ulaval.ca>