Client and Transport are reusable and thread safe, so
initialize once and reuse across requests. Also close the response
body properly by consuming it fully before closing it to allow
the underlying RoundTripper to reuse the transport for subsequent
requests.

Change-Id: I1d1692ee96db1ed91a0eaccbe81439312c6935ac
Signed-off-by: Balaji Viswanathan <balaji.viswanathan@gmail.com>
Signed-off-by: denyeart <enyeart@us.ibm.com>