Revert "MB-10468 determine document type within view engine"

This reverts commit b9ae83f853671d0373bc6ba53c2a8f03a5eb717c.

The previous commit makes this one obsolete. The data type of a document
no longer needs to be determined within the view-engine, UPR provides that
information.

Change-Id: Idf2a5fc4ed6efa60b9d7ae196da71ded2b80dffd
Reviewed-on: http://review.couchbase.org/36704
Reviewed-by: Nimish Gupta <nimish@couchbase.com>
Reviewed-by: Filipe David Borba Manana <fdmanana@gmail.com>
Tested-by: buildbot <build@couchbase.com>