Checkmk Werk 11624: Legacy checks: fix usage of discovery rulesets

ID: 11624 Title: Legacy checks: fix usage of discovery rulesets Component: Checks & agents Level: 1 Class: Bug fix Version: 2.0.0i2 For certain legacy checks, some discovery rulesets were not applied correctly (e.g. the discovery ruleset "Filesystem grouping patterns" for the <tt>df</tt>-check). This has been fixed.