install the classloader associated with some specific recovery module as the current thread's class loader
this avoids a problem where the background periodic recovery thread can see the same class as the recovery
module's class loader, specifically where a the recovery module resides in a sar (e.g. the XTS code).
If class with name "A" is loaded via the background thread class loader as A' and used to create instance
a' then a cast expression in th erecovery code of the form (A)a' will try to resolve a' against version
A'' loaded via the sar loader and get a class cast exception.