When the construction of a member of Packet_stream_*::Rpc_object after
the _cap member threw an exception, the object was not dissolved from
the entrypoint although the Rpc_object vanished at this point. This was
because the call to 'manage()' happened in the initializer list (for the
_cap member instantiation). The destruction of the _cap member then did
not dissolve the object.
This first fix moves the call to 'manage()' into the constructor body
after the instantiation of all other members. A more sophisticated fix
would use some kind of 'Managed_object' life-time guard that manages an
object on construction and dissolves on destruction.
Ref #3525
60d37f690c