Add a reference on a timer in a mock of a connection
Add a reference on a timer in a mock of a connection

We suspect that it was garbage collected in some cases, which would make
the node wait forever on the connection.

Change-Id: Ib4a6557abf24501f8d8ab27d32da46fe1f6bb559
JIRA: WBSC-3077

criteo/kafka-sharp,criteo/kafka-sharp