gplazma: Remove internal principals from reply

Addresses compatibilty issues between 2.2 head nodes and 1.9.12 pools.

Some plugins, like the kpwd plugin, do not fill well into gPlazma 2's
architecture. The kpwd file plays the role of all four steps of a
gPlazma login and the plugin must do tricks to pass information from
one phase to the next. It does this by injecting a KpwdPrincipal that
holds the kpwd record.

Unfortunately, this principal escapes gPlazma and is passed along to
other dCache components as part of the Subject. Besides exposing
plugin specific internal principals, and making the subject unnecessarily
larger, this poses a compatbility problems with 1.9.12 pools - these
pools do not have the means to deserialize the internal KpwdPrincipal.

This patch solves the problem by removing all non-public principals
before constructing the gPlazma reply.

Target: trunk
Request: 2.6
Request: 2.2
Require-notes: yes
Require-book: no
Patch: http://rb.dcache.org/r/5487/
Acked-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de>
pool: Make access time update non-blocking

Addresses a performance issue when reading files from a pool.

Patch http://rb.dcache.org/r/4568/ modified the pool to let access
time be updated whenever a file is read. The update is however blocking,
which means that the notification thread in the pool is blocked until
a reply from PnfsManager is received. Given that we do not use the
reply for anything, we can just as well turn the access time update
into a non-blocking notification.

Target: trunk
Request: 2.6
Require-notes: no
Require-book: no
Acked-by: Dmitry Litvintsev <litvinse@fnal.gov>
Acked-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de>
Patch: http://rb.dcache.org/r/5472/
Merge pull request #2 from dCache/fix/2.6/gplazma-internal-principals

gplazma: Remove internal principals from reply
Merge pull request #4 from dCache/fix/2.6/pool-atime-notification

pool: Make access time update non-blocking