roadmap/3.8: move "Throttling xlator" to the next release
roadmap/3.8: move "Throttling xlator" to the next release

The developers working on the "Throttling xlator" informed me that they were
not able to spend enough time on the feature and it will not be ready for
testing by users when 3.8 is released.

Moving the feature to the next release.

Signed-off-by: Niels de Vos <7bda0c0ee7f47171cc808e9e60292cbc5d8140dd@redhat.com>
gluster/glusterweb,gluster/glusterweb,gluster/glusterweb,anoopcs9/glusterweb,gluster/glusterweb,anoopcs9/glusterweb,anoopcs9/glusterweb,anoopcs9/glusterweb