Use single file etap

The bundled etap in couchdb got updated, hence no
hacks are needed any more.

Change-Id: I27cb726240eb91c03fb25032e2ed197494a47ffd
Reviewed-on: http://review.couchbase.org/40132
Reviewed-by: Volker Mische <volker.mische@gmail.com>
Tested-by: Volker Mische <volker.mische@gmail.com>