Fix configuration cache invalidation

Addresses several issues with configuration cache invalidation.
The symptom of these problems was that the cache was not
invalidated when it should have been.

Specifically:

Fixes an inconsistency between bash and other shell in which
the -ot test behaves differently when the left hand file does
not exist.

Fixes an issue with host name change detection on Mac OS.

Fixes an issue detect that dcache.conf was added.

Target: trunk
Request: 2.7
Request: 2.6
Require-notes: yes
Require-book: no
Acked-by: Paul Millar <paul.millar@desy.de>
Patch: http://rb.dcache.org/r/6293/
Ticket: http://rt.dcache.org/Ticket/Display.html?id=8131
cells: Associate threads and initialization messages with their cell

Use the cell name in threads. Do more cell initialization in
a thread associated with the cell, thus directing log messages
to the proper pinboard.

Target: trunk
Require-notes: no
Require-book: no
Acked-by: Paul Millar <paul.millar@desy.de>
Patch: http://rb.dcache.org/r/6282/
cells: Move dCache's cell interfaces into cells

These interfaces were originally placed outside of cells
as cells was a closed product. Now that cells is part of
dcache, there is no reason not to move those interfaces
to the proper place.

This allows the LoginBrokerHandler utility class to be
moved to the same package on the LoginManager it is coupled
to. A future patch will update LoginManager to use that
utility class and thus avoid the code duplication with an
internal class.

This patch only moves classes. Besides deleting the unused
ThreadFactoryAware, there are no code changes.

Target: trunk
Require-notes: no
Require-book: no
Acked-by: Paul Millar <paul.millar@desy.de>
Patch: http://rb.dcache.org/r/6285/
system-test: add nfsv41 into default configuration

no portmap/rpcbind required.

Acked-by: Gerd Behrmann
Target: master
Require-book: no
Require-notes: no