Changes

Fix tests for Apache HTTP Client 4.5 and greater

Must explicitly close the underlying HttpClient instance to ensure
pooled connections are closed between between tests.  Otherwise stale
connections exist from previous test and which fail on use with
NoHttpResponseException errors.

https://hc.apache.org/httpcomponents-client-4.5.x/current/tutorial/html/connmgmt.html#d5e401

Change-Id: I318ea1006e8d7453d95960f5d33bbff2bb36735a
Signed-off-by: Brian de Alwis <bsd@acm.org>