Howto troubleshoot error after Drupal upgrade to 7.31, 7.32, 7.33, 7.34, 7.35, 7.36, 7.37, 7.38, 7.39 (Notice: Undefined index)

After the the upgrade to the recent Drupal version (in our example Drupal 7.31 - 7.34) you might get one of these errors: Notice: Undefined index: name in system_requirements() (line 34 in ../modules/system/system.install) or Notice: Undefined index: version in system_requirements() (line 36 in ../modules/system/system.install), solution is the same! This howto shows you how to troubleshoot this error.