[views] fix ProcessInformationView: SESSION_MANAGER can be None (closes #5753280)
eg. with pyramid.
(grafted from 6a07c2dc3d85f4de0cf48221607e02c4473e11e4)
usr/lib/PY_VERSION/*-packages/cubicweb/server/
usr/lib/PY_VERSION/*-packages/cubicweb/hooks/
usr/lib/PY_VERSION/*-packages/cubicweb/sobjects/
usr/lib/PY_VERSION/*-packages/cubicweb/schemas/
usr/share/cubicweb/migration/