JSCBC-1092: Fix queries to default to adhoc rather than prepared.

Motivation
----------
The 3.x SDK and SDK design guidelines describe that queries should
be adhoc by default, and should only prepare queries when explicitly
requested.

Changes
-------
Changed the adhoc value calculation to default appropriately.

Change-Id: I189c967039c824224a5b3036bef0f77a2e642a13
Reviewed-on: https://review.couchbase.org/c/couchnode/+/178493
Reviewed-by: Charles Dixon <chvckd@gmail.com>
Tested-by: Brett Lawson <brett19@gmail.com>

lib/queryexecutor.ts

@@ -130,7 +130,7 @@ export class QueryExecutor {
         {
           statement: query,
           client_context_id: options.clientContextId,
-          adhoc: options.adhoc || false,
+          adhoc: options.adhoc === false ? false : true,
           metrics: options.metrics || false,
           readonly: options.readOnly || false,
           flex_index: options.flexIndex || false,