Boring pdnsutil cleanups

[miodvallat]

Short description

This boring PR boringly addresses coverity complaints about pdnsutil, as well as some easy-to-do clang-tidy ones.

Checklist

I have:

• read the CONTRIBUTING.md document
• compiled this code
• tested this code
• included documentation (including possible behaviour changes)
• documented the code
• added or modified regression test(s)
• added or modified unit test(s)
• warned people that this is a boring PR multiple times

[coveralls]

Pull Request Test Coverage Report for Build 12833904435

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 16 unchanged lines in 5 files lost coverage.
• Overall coverage increased (+0.04%) to 64.732%

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Files with Coverage Reduction	New Missed Lines	%
pdns/recursordist/sortlist.cc	2	72.94%
modules/lmdbbackend/lmdbbackend.cc	2	73.7%
pdns/packethandler.cc	3	72.35%
pdns/iputils.cc	3	56.84%
pdns/recursordist/test-syncres_cc1.cc	6	89.8%

Totals
Change from base Build 12832418127:	0.04%
Covered Lines:	127851
Relevant Lines:	166436

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💛 - Coveralls