dispatch: enforce edge-triggered mode
dispatch: enforce edge-triggered mode

Our API is modeled around edge-triggered signalling. Enforce EPOLLET in
the dispatch-file API so everything is properly handled. Note that our
API is unusable for level-triggered mode, since kernel-interest cannot
be cleared. From a dispatch-file viewpoint it would work fine, but the
dispatch context would busy-loop.

Signed-off-by: David Herrmann <fb53b2ddb8d141e0cb39d7c67c2f81b6bc2eb0f7@gmail.com>

bus1/dbus-broker