MB-9495: notify threads on task wake to avoid loss

To avoid a lost post from the pthread's signal routine
notify all threads on a task wake

This change benefits not only bg fetch task but also flusher

Change-Id: I1ad37d11dc9b256bd4b88a1b6860fbf10d22cfcf
Reviewed-on: http://review.couchbase.org/30196
Reviewed-by: Chiyoung Seo <chiyoung@couchbase.com>
Tested-by: Chiyoung Seo <chiyoung@couchbase.com>
MB-9499: sync up ns-server ht_size in prime table

ns-server initializes hash table with 3079 which is a prime
closest value in ep-engine's prime table is 3067 which causes
an unnecessary resize operation which can be avoided.

Change-Id: I66d3d2fb2cb9bf6888c745a4bdc1d419ff791e2e
Reviewed-on: http://review.couchbase.org/30197
Reviewed-by: Chiyoung Seo <chiyoung@couchbase.com>
Tested-by: Chiyoung Seo <chiyoung@couchbase.com>