dcache-webadmin: fix pool queue plot grid placeholder image

The pool queue plot grid is computed to find the best square fit up to 8 X 8 of plots.
This means that there will remainders (blanks) for all but the square cases.
Previously the placeholder was an empty symbol denoting no pool, but this particular
image was not the right size and at any rate was rather ugly.

The patch replaces the previous image with a simple blank image the same size as the plots.

Target:  2.6
Require-notes: no
Require-book: no
Acked-by: Dmitry
Committed: 7fed8893e0e718cd053f80e6ae3f4c432d4ed9fe
pool: Fix race condition that leads to orphaned files

Using FileNotInCacheException cause the chimera registration to be cleared.
Clearly we don't want this when the file is actually in the pool and just
happens to be in a state in which it isn't accessible.

This patch changes the exception to LockedCacheException.

This is an alternative to patch: https://rb.dcache.org/r/5801

Target: trunk
Request: 2.9
Request: 2.8
Request: 2.7
Request: 2.6
Request: 2.2
Require-notes: yes
Require-book: no
Acked-by: Paul Millar <paul.millar@desy.de>
Patch: https://rb.dcache.org/r/7103/
(cherry picked from commit ade506eb0c921bdeb4284d42e7c247794b3e5d1a)
Merge pull request #687 from gbehrmann/fix/2.6/rb7103

pool: Fix race condition that leads to orphaned files
fixed the Wicket utils import statement
Merge pull request #676 from alrossi/fix/2.6/pqp_placeholder

dcache-webadmin: fix pool queue plot grid placeholder image
[maven-release-plugin] prepare release 2.6.31
[maven-release-plugin] prepare for next development iteration
deb: Add python-psycopg2 as a recommended dependency

Needed by dcache-star.

Target: trunk
Request: 2.9
Request: 2.8
Request: 2.7
Request: 2.6
Require-notes: yes
Require-book: yes
Acked-by: Paul Millar <paul.millar@desy.de>
Patch: https://rb.dcache.org/r/7091/
(cherry picked from commit efa2de674ac1ca5aa1b18d0aba186ee98c4ead22)
alarms: Fix checksum alarm filter.

The filter provided for checksum alarms generated by the pool scrubber
is out of sync with the actual logging statement in the scrubber.

This patch fixes the regex for the filter to match.

Target: 2.6
Require-book: no
Require-notes: yes
Acked-by: Karsten
Acked-by: Paul

RELEASE NOTES

Fixes a bug present since April 2013 (but up to now undiscovered by us) preventing
reporting of checksum alarms from the pool scrubber.
Merge pull request #693 from gbehrmann/fix/2.6/rb7091

deb: Add python-psycopg2 as a recommended dependency
Merge pull request #697 from alrossi/fix/2.6/checksum_alarm_filter

alarms: Fix checksum alarm filter.