CBLT-252:  define MAVEN_LOCAL_REPO before env.vars. are written to log

Change-Id: I46b55d09cfa23f489c93d64ba75539572948318d
Reviewed-on: http://review.couchbase.org/35220
Reviewed-by: Philip Labee <philip@couchbase.com>
Tested-by: Philip Labee <philip@couchbase.com>