Partial revert of r1511907.
Suppress unchecked warnings as they can;t be avoided.
Revert r1519804
Remove use of createMissingPackageInfoClass which requires Ant 1.8.3

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1524107 13f79535-47bb-0310-9956-ffa450edef68