Add session persistence support to LBaaS HAProxy driver

fixes bug 1135324

Change-Id: I5bcd6c84d6b402adecfb5a4cf81925ddbefccbb0
Add stats reporting to HAProxy namespace driver

fixes bug 1135327

Change-Id: Ib5bc1b66ba57a8d93a5ee181c7cde64893c6b651
Merge "Add session persistence support to LBaaS HAProxy driver"
Merge "Add stats reporting to HAProxy namespace driver"