Mongoid has removed options for Factory#build

Passing without_protected: true is no longer valid. Mongoid now
relies on ForbiddenAttributesProtection for this.

see: https://github.com/mongoid/mongoid/commit/33bd65d38754fb07aed533b0c0b15a31087fae87
mongo_session now checks for persistence options already

We don't need to clear persistence options.
See https://github.com/mongoid/mongoid/commit/af65a1bf78eb1b4d57904a843c628c09aadab0dd
Added test case for forcing document revision

Even if the document has not changed, revise! should
create a version