Send "Connection: close" with Ping commands

* This is being done as requested by $VENDOR to help with an
  issue related to inappropriate network activity following a
  "Ping" command
* This change will increase overhead during runPingLoop, as
  the connection must be rebuilt each pass, and it is possible
  that other unexpected side-effects will occur

Bug: 5420438
Change-Id: I1e3f5b60566f08d9b107e5648e5e68030e3dbb5e
1 file changed