HTTPCORE-373: out of sequence HTTP response causes NPE in HttpAsyncRequestExecutor

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/httpcore/branches/4.3.x@1567106 13f79535-47bb-0310-9956-ffa450edef68
Improved exception handling in HttpAsyncService

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/httpcore/branches/4.3.x@1567578 13f79535-47bb-0310-9956-ffa450edef68
Updated HttpCore 4.3.2 release notes

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/httpcore/branches/4.3.x@1567749 13f79535-47bb-0310-9956-ffa450edef68
Merge remote-tracking branch 'asf/4.3.x' into 4.3.x
HTTPASYNC-69: async request handler is closed by HttpAsyncRequestExecutor#closed if the underlying connection is found to be in an incossitent state