Keep auth headers out of the StringCache

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1459074 13f79535-47bb-0310-9956-ffa450edef68
Buidlbot needs a little longer

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1459075 13f79535-47bb-0310-9956-ffa450edef68
Ensure HEAD requests return the correct content length when the requested resource uses a Writer.
Patch by Nick Williams.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1459085 13f79535-47bb-0310-9956-ffa450edef68