gplazma: ldap: fix closed connection problem

This patch fixes the problem of CommunicationException due to externally
closed connections (e.g., by a firewall) and it introduces unit tests
for all public methods of the plugin.

Acked-by: Tigran
Target: master
Request: 2.7
Require-book: no
Require-notes: no
srm: Clean up srmPrepareToGet

Target: trunk
Require-notes: no
Require-book: no
Acked-by: Paul Millar <paul.millar@desy.de>
Patch: http://rb.dcache.org/r/6136/
srm: Clean up srmPrepareToPut

Target: trunk
Require-notes: no
Require-book: no
Acked-by: Paul Millar <paul.millar@desy.de>
Patch: http://rb.dcache.org/r/6138/
nfs: fall back to numeric mapping by default

Linux client uses number based mapping by default.
This makes dCache default configuration to have
'bad' behaviour. Let make our default same as linux
has.

Acked-by: Paul Millar
Target: master, 2.6
Require-book: no
Require-notes: yes