[hotfix] Log interrupted exception on debug when closing threads in ExternalSorter

[dawidwys]

What is the purpose of the change

Revert the behaviour of logging an InterreputedException on debug level when closing working threads in ExternalSorter.

Verifying this change

This change is a trivial rework / code cleanup without any test coverage.

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• Dependencies (does it add or upgrade a dependency): (yes / no)
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• The S3 file system connector: (yes / no / don't know)

Documentation

• Does this pull request introduce a new feature? (yes / no)
• If yes, how is the feature documented? (not applicable / docs / JavaDocs / not documented)

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Last check on commit 0602dad (Fri Oct 16 15:34:17 UTC 2020)

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[rmetzger]

Except for a tiny naming problem, this is good to go.

[rmetzger]

Suggested change

	private void closeThread(StageRunner sortThread, String threadName) {
	private void closeThread(StageRunner thread, String threadName) {

[rmetzger]

Suggested change

	sortThread.close();
	thread.close();