[migration] move CWComputedRType later The ordering in this file is a mess, and things don't actually work this way (when upgrading from 3.17).

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