PersistentValve is broken as it stands and always delete sessions right after it creates them.  

cf. the following lines in https://github.com/apache/tomcat/blob/TOMCAT_7_0_42/java/org/apache/catalina/valves/PersistentValve.java#L178-L179

  store.save(session);
  ((PersistentManager) manager).removeSuper(session);


I have setup my PersistentManager with a JDBCStore, and if I set a breakpoint between these two lines, I can see the `save` call inserts a row into the database properly, and then take one step past the `removeSuper` call, and it deletes the row from the database.

The removeSuper (used by PersistentValve) method has the following comment on it:
"Remove this Session from the active Sessions for this Manager, but not from the Store."

The implementation of remove in PersistentManagerBase has the following comment:
"Remove this Session from the active Sessions for this Manager, and from the Store."

There is clearly a break in the API here. The PersistentValve is expecting the PersistentManager.removeSuper to do one thing (which method has a comment saying it exists only for the sake of PersistentValve, btw.), but PersistentManagerBase which implements this does a different thing than expected.