Remove explicit paralleloptions from overload

For this overload, were relying on the task scheduler to determine the
number of concurrent operations to process. If you explicitly need to set
the MaxDegreeOfParallism, use one of the overloads that takes a
ParallelOptions class and set the MaxDegreeOfParallism there.

Change-Id: I152d156f8bacf7e3d17a6ea6fbd0886486c472b6
Reviewed-on: http://review.couchbase.org/41780
Tested-by: Jeffry Morris <jeffrymorris@gmail.com>
Reviewed-by: Brett Lawson <brett19@gmail.com>