Remove assertion about self handle after connection disposal

Signed-off-by: Martti Piirainen <martti.piirainen@oss.tieto.com>
Merge pull request #10 from marttipiirainen/connection_disposal_crash

Remove assertion about self handle after connection disposal
Retry call hangup once if it failed (e.g. due to ongoing modem request)

Signed-off-by: Martti Piirainen <martti.piirainen@oss.tieto.com>
Merge pull request #11 from marttipiirainen/hangup_retry

[telepathy-ring] Retry call hangup once if it failed (e.g. due to ongoing modem request)