Revert "CBQE-0: Changing the default batch size for async load to 1000"

This reverts commit d5be9e3f86f290aabd398b6df8e78a54585bd621.

Change-Id: I6d898f029f6e83ed99cc127a443942b32d5225f1
Reviewed-on: http://review.couchbase.org/40281
Reviewed-by: Aruna Piravi <aruna@couchbase.com>
Tested-by: Aruna Piravi <aruna@couchbase.com>