jsonrpc: ssl reconnect issue and spelling mistake

When vdsm crashes there was stale channel which did not
let client to reconnect after attempt threshold. This issue
is fixed by nulling the channel.

There was spelling mistake in ManagerProvider in the method 
getTrustManagers and it was fixed.


Change-Id: I03e5672e554d9b3abe0bb7fb61e897ddeffe8c3b
Signed-off-by: pkliczewski <piotr.kliczewski@gmail.com>