Explicitly restrict HTTP upgraded connections to a max of one thread for read and another for write.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1476972 13f79535-47bb-0310-9956-ffa450edef68
Fix some ISEs that were appearing in the logs.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1476996 13f79535-47bb-0310-9956-ffa450edef68