cubicweb #2361061 crash on upgrade to cw 3.15 [validation pending]

Execute '/home/auc/src/fcw/cubicweb/misc/migration/' ? [Y/n/s(how)/a(bort)]:
Traceback (most recent call last):
File "/home/auc/src/fcw/cubicweb/", line 167, in run_arg
status = cmdmeth(appid)
File "/home/auc/src/fcw/cubicweb/", line 767, in upgrade_instance
mih.migrate(vcconf, reversed(toupgrade), self.config)
File "/home/auc/src/fcw/cubicweb/server/", line 155, in migrate
super(ServerMigrationHelper, self).migrate(vcconf, toupgrade, options)
File "/home/auc/src/fcw/cubicweb/", line 181, in migrate
File "/home/auc/src/fcw/cubicweb/server/", line 160, in cmd_process_script
migrscript, funcname, *args, **kwargs)
File "/home/auc/src/fcw/cubicweb/", line 350, in cmd_process_script
execfile(migrscript, scriptlocals)
File "/home/auc/src/fcw/cubicweb/misc/migration/", line 1, in <module>
undo_actions = config.cfgfile_parser.get('MAIN', 'undo-support', False)
File "/usr/lib/python2.6/", line 541, in get
raise NoOptionError(option, section)
NoOptionError: No option 'undo-support' in section: 'MAIN'
instance pagode not upgraded: No option 'undo-support' in section: 'MAIN'

done in3.15.1
load left0.000
closed by#eb6a607a0067 [migration] do not crash if the conf file is already migrated (closes #2361061)