Fixed problem with detecting session ID if response contains multiple Set-Cookie headers.

One of our customers ran into a problem when using memcached-session-manager in their application. After some debugging, we saw that one of our filters added a Set-Cookie header for our own cookie before Tomcat could add its Set-Cookie header for JSESSIONID. 

We think that memcached-session-manager should check all Set-Cookie response headers instead of only the first one in method RequestTrackingHostValve::getSessionIdFromResponseSessionCookie.