Remove dtrace support

At the moment logging framework is more maintainable that these hooks

Change-Id: I2805a32c6c1cb9c466632b633954506ac129d364
Reviewed-on: http://review.couchbase.org/33329
Tested-by: Sergey Avseyev <sergey.avseyev@gmail.com>
Reviewed-by: Mark Nunberg <mnunberg@haskalah.org>