CBQE-0 : use POST to run n1ql queries instead of GET

Change-Id: I0e4851513b3c3f72498d2c1fc6c01472258468c9
Reviewed-on: http://review.couchbase.org/42566
Reviewed-by: Iryna Mironava <irynamironava@yandex.ru>
Tested-by: Iryna Mironava <irynamironava@yandex.ru>