Ensure that when the Default or WebDAV servlets process an error dispatch that the error resource is processed via the doGet() method irrespective of the method used for the original request that triggered the error.

      git-svn-id: https://svn.apache.org/repos/asf/tomcat/tc8.5.x/trunk@1793488 13f79535-47bb-0310-9956-ffa450edef68