BUG-2510: Remove all registrations when a routed rpc is closed

The API contract specifies that the effects of a Registration are
removed on close(). Unfortunately the routed RPC case is more funny, as
it has sub-registrations, for each added path -- and we have no mention
of the fact that the user should be removing them.

Hence we need to handle the user expecting us to remove any and all
paths which have been registered.

Change-Id: Iedf451c2a481d648173819f895cccb9e63c54d99
Signed-off-by: Robert Varga <rovarga@cisco.com>
(cherry picked from commit 940751adf968a6789514566281bb0817bbf07878)
BUG-2510: handle RPC route removal

DOM to Binding forwarding ignored removals of RPC implementations. Add
that case back.

Change-Id: I7af1d8b43b9b229cc9a696cfdfc61146f960b374
Signed-off-by: Robert Varga <rovarga@cisco.com>
(cherry picked from commit 11380c5b8bc0d9831ed182ed758a74f66278df78)
Merge "BUG-2510: handle RPC route removal" into stable/helium