Revert TAP connection notification improvements.

We saw high CPU overhead regression from TAP connection
notification improvements, which was caused by a different
thread scheduling in 3.0.

Change-Id: Icc9ecfcbcee499d1c4ac8b3da67eb337254bb586
Reviewed-on: http://review.couchbase.org/37114
Reviewed-by: Chiyoung Seo <chiyoung@couchbase.com>
Tested-by: Chiyoung Seo <chiyoung@couchbase.com>