MB-7462: Always declare static before const in variable declarations

This makes our code conformable with cpplint checking

Change-Id: I7bbc3f87520312b07026ad06fd918a103d492b09
Reviewed-on: http://review.couchbase.org/23516
Reviewed-by: Jin Lim <jin@couchbase.com>
Tested-by: Michael Wiederhold <mike@couchbase.com>