Check_MK Werk 3649: Added a workaround for an escaping-related bug in old bash versions

ID: 3649 Title: Added a workaround for an escaping-related bug in old bash versions Component: Checks & Agents Level: 1 Class: Bug Fix Version: 1.4.0i2 Some old bash versions (up to 3.2.x) had a slightly obscure bug regarding the escaping of special characters in regular expression matches, so a workaround for this was necessary.