[devtools] don't hide warnings and errors during tests
The markdown module in jessie turns all warnings into logging calls, so
this allows me to still see deprecation warnings when running tests.
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/