dcache, webadmin: fix exception handling

This commit covers three patches:

http://rb.dcache.org/r/6022/
http://rb.dcache.org/r/6029/
http://rb.dcache.org/r/6030/

BILLING:

A number of checked exceptions which were wrapping unchecked exceptions have been eliminated.  In general RuntimeExceptions are propagated. Two exceptions:  when generating JAIDA plots, and within the webadmin refresh() call to the billing service.  In the latter case, JVM errors are propagated, but RuntimeExceptions simply cause the the loop to exit.

CORE, XACML, WEBADMIN:

Code in several places is not handling exceptions correctly; in particular, RuntimeExceptions masked by Exception are occasionally being caught and not propagated.

Where it is possible, catch(Exception) has been eliminated; where not possible, catch(RuntimeException) is called first so that this exception can be rethrown.

In several cases, a RuntimeException (such as the JDOExceptions from DataNucleus) are not propagated, as they cannot reasonably be handled elsewhere, and they should not be fatal to the JVM in any case.

A separate set of patches have been reviewed for 2.6.

Testing:

Junit tests rerun.  Deployed and checked.

Target: master
Request: 2.6
Acked-by: Karsten
Acked-by: Tigran
Acked-by: Dmitry
Require-notes: no
Require-book: no