Review where we're passing WT_CONNECTION_IMPL instead of WT_SESSION_IMPL,
and for that reason directly accessing WT_CONNECTION_IMPL.default_session,
prefer passing the session handle instead of the connection handle where
that makes sense.
Merge branch 'develop' into connection-vs-session-cleanup
Merge branch 'develop' into connection-vs-session-cleanup
Merge branch 'develop' into connection-vs-session-cleanup
Merge pull request #1219 from wiredtiger/connection-vs-session-cleanup

Review where we're passing WT_CONNECTION_IMPL instead of WT_SESSION_IMPL