JCBC-587: Never quote start/endKeyDocId in the ViewQuery

Motivation
----------
start/endKeyDocIDs are never JSON and therefore are not allowed to be quoted,
breaking the queries when used from the SDK.

Modifications
-------------
Quotes have been removed to correctly send it over HTTP to the view engine.

Result
------
Both fields can now be properly utilized in a view query.

Change-Id: I888d1e4d8f809e5c00ddcd202287c44bef0aed49
Reviewed-on: http://review.couchbase.org/42158
Tested-by: Michael Nitschinger <michael.nitschinger@couchbase.com>
Reviewed-by: Sergey Avseyev <sergey.avseyev@gmail.com>
Reviewed-by: Volker Mische <volker.mische@gmail.com>
Reviewed-by: Simon Baslé <simon@couchbase.com>