[migractions] add a dropped_constraints() migration command
Example usage:
>>> with dropped_constraints('MyType', 'myattr',
... UniqueConstraint, droprequired=True):
... add_attribute('MyType', 'myattr')
... # + instructions to fill MyType.myattr column
...
>>>
/var/log/cubicweb/*.log {
weekly
missingok
rotate 10
compress
delaycompress
notifempty
create 640 root adm
sharedscripts
postrotate
if [ -x /usr/sbin/invoke-rc.d ]; then \
invoke-rc.d cubicweb reload > /dev/null 2>&1; \
else \
/etc/init.d/cubicweb reload > /dev/null 2>&1; \
fi; \
endscript
}