Metric added that will record the time a request to couch db takes to
complete.

Change-Id: Ie2068bb7b97a7103306093a2a6618ed0caed6b4b
Signed-off-by: Saad Karim <skarim@us.ibm.com>
Signed-off-by: Matthew Sykes <sykesmat@us.ibm.com>