[server] Use global registry variable of integrity checker functions Instead of querying globals() in checkintegrity.check(), we maintain a _CHECKERS dict mapping checker name to function in checkintegrity module. This is later used to build the list of available checkers in 'db-check' command help.

version=3
opts=uversionmangle=s/(rc|a|b|c)/~$1/ \
https://pypi.debian.net/cubicweb/cubicweb-(.+)\.(?:zip|tgz|tbz|txz|(?:tar\.(?:gz|bz2|xz)))