Fix various database-related niggles

This patch fixes a number of relatively minor database-related irritations:

  1. When dCache starts, the SRM's AuthRecord persistency BoneCP db-pool emits a

         Max Connections < 1. Setting to 20

     warning.  This is fixed by specifying the maximum number of connections.

  2. Remove the unnecessary 'provider' from JDO persistence-unit stanza (we're no
     longer using TopLink, so this work-around is not needed any more).

  3. Fix various unit-tests to configure BoneCP's max connections, so they no
     longer emit the "Max Connections < 1" warning.

  4. Remove a dead-code line from database initialisation (used by space-manager
     and replica-manager).  The dead-code is likely due to a typo ("Min" vs "Max")
     but, to avoid possible side-effects, this patch simply removes the dead-code.

  5. Fix AuthRecordPersistenceUnit configuration so that DataNucleus' (JPA) enhancer
     no longer attempts to modify the byte-code of all dCache classes, but only
     those necessary.  This makes the build *much* less noisy and slightly
     faster.

When the DataNucleus' (JDO) enhancer modifies classes for the pin-manager, only a single
class needs enhancing (org.dcache.pinmanager.model.Pin), however the enhancer reports
that some 30 classes were considered.  I don't know which 30 classes are examined, nor
why the enhancer is examining classes other than Pin.

Patch: http://rb.dcache.org/r/5687/
Acked-by: Albert Rossi
Target: trunk
Requires-notes: no
Requires-book: no