This adds a new link to the OPS page called "List all-error Workunits".
The php script it calls scans the database for Workunits that got at
least min_quorum+1 (number can be configured withing the script)
client errors returned and no successful result (yet). The idea is to
detect problems in the workunit generation or data files.
Scanning the whole result table the script stresses the database a bit,
so some caching has been incorporated (300 sec by default).
svn path=/trunk/boinc/; revision=11250