[web/views] fix editcontroller regression unittest_views_basecontrollers.py's EditControllerTC.test_edit_mandatory_inlined3_object regressed with changeset dcbb64d3a1d9 because it relied on POSTing nonexisting eids. This seems like a silly idea, but let's keep the behaviour unchanged.

import ConfigParser
try:
    undo_actions = config.cfgfile_parser.get('MAIN', 'undo-support', False)
except ConfigParser.NoOptionError:
    pass # this conf. file was probably already migrated
else:
    config.global_set_option('undo-enabled', bool(undo_actions))