MB-100: rem logger declaration from basetestcase

Change-Id: I4c9b3e27baca10b16dc5a0e401839eb765f09b86
Reviewed-on: http://review.couchbase.org/23665
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Andrei Baranouski <andrei.baranouski@gmail.com>