Fix session logging

We are using 'this' for session name -- that refers to the anonymous
class, leading to confusing logs. Fix that by passing the proper
session. This allows us to use a simple lambda instead.

Change-Id: I10080ef1f55d260af3a1ca8b62a58510d0feec87
Signed-off-by: Robert Varga <robert.varga@pantheon.tech>