File signl4.py in 2.2.0 should be the same as in 2.3.0

[rons4]

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General information

File signl4.py in 2.2.0 should be the same as in 2.3.0. Some things have been fixed there already.

Bug reports

Please include:

Basically, same as here: https://github.com/Checkmk/checkmk/pull/603 But for 2.2.0 (not only for 2.3.0).

Proposed changes

Same as for pull request #603. Already tested there.