Fix test migration crash waiting to happen due to inferred relations Avoid crashing when a relation definition which is already known (due to being inferred) gets explicitly added. As explained in a comment, this would deserve more thinking, but at least this fixes a test failure with computed relations.

#!/bin/sh -e
if [ "$1" = "purge" ] ; then
        update-rc.d cubicweb remove >/dev/null
fi
 
#DEBHELPER#
 
exit 0