Connection on onMessageProcess captured as copy

Connection on onMessageProcess captured as copy

Connection can be abnormally closed by the peer and with
std::shared_ptr<Connection> &, it's hardly guarantee validity of the
reference. So we capture std::shared_ptr<Connection> as copy so
increment shared pointer's reference so as to guarantee validity of
connection. Catch exceptions when using connection in process of
onMessageProcess because the connection could be already closed by the
peer.

Change-Id: I391bae78cf663b875b96124f8356d27a38a97dc6
Signed-off-by: Kyungwook Tak <k.tak@samsung.com>