[massive store] master_init should commit by default
Default client usage is to create a master store to control
slave ones. They need to access cwmassive_initialized from
another transaction
usr/lib/python2*/*-packages/cubicweb/web
usr/lib/python2*/*-packages/cubicweb/wsgi
usr/share/cubicweb/cubes/shared/data
usr/share/cubicweb/cubes/shared/wdoc