RequestContext's are not held by DeviceContext anymore

RequestContext's are not held by DeviceContext anymore

All necessary work is done in callbacks registered when commiting entry in  outbound queue.
That makes registration of req. context inside device context worthless. Collection of
multiparts is done in message collector on request context registered when entry is commited.
Request contexts not held by DeviceManager and barrier reuqests issued by OFJ makes
OutsandingMessageExtractor useless as well.

Change-Id: Ib259020ed4e3cca56463696827bb24bf7bc97069
Signed-off-by: Martin Bobak <mbobak@cisco.com>