Fix https://issues.apache.org/bugzilla/show_bug.cgi?id=56657#c2
Ensure that re-mapping selects the context version that we expect.
Merged r1604661 from tomcat/trunk.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/tc7.0.x/trunk@1604662 13f79535-47bb-0310-9956-ffa450edef68