rec: Only log MOADNSExceptions if logging.log_common_errors is true.

[omoerbeek]

But do not ratelimit them. Note that MOADNSExceptions is derived from std::runtime_errror and not from std::exception.

Also introduce the same logic related to gettag() in rec-tcp.cc compared to pdns_recursor.cc.
Churn is a bit high as s_rateLimitedLogger changed into g_rateLimitedLogger, to make it available in rec-tcp.cc.

Fixes #14582

Short description

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)

[coveralls]

Pull Request Test Coverage Report for Build 10633018362

Details

• 5 of 25 (20.0%) changed or added relevant lines in 3 files are covered.
• 98 unchanged lines in 16 files lost coverage.
• Overall coverage decreased (-0.02%) to 64.643%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pdns/recursordist/rec-tcp.cc	3	7	42.86%
pdns/recursordist/pdns_recursor.cc	1	7	14.29%
pdns/recursordist/rec-main.cc	1	11	9.09%

Files with Coverage Reduction	New Missed Lines	%
pdns/recursordist/rec-tcp.cc	1	65.73%
pdns/recursordist/rec-main.cc	1	61.89%
pdns/pollmplexer.cc	1	83.66%
pdns/sstuff.hh	2	56.83%
pdns/backends/gsql/gsqlbackend.hh	2	97.71%
pdns/misc.cc	2	63.43%
pdns/recursordist/test-syncres_cc2.cc	3	88.91%
pdns/stubresolver.cc	3	77.58%
pdns/recursordist/recpacketcache.hh	3	89.55%
pdns/shuffle.cc	4	39.71%

Totals
Change from base Build 10612335851:	-0.02%
Covered Lines:	124625
Relevant Lines:	162099

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💛 - Coveralls

[rgacogne]

But do not ratelimit them. Note that MOADNSExceptions is derived from std::runtime_errror and not from std::exception.

Something is weird here, because std::runtime_error derives from std::exception.

[omoerbeek]

I misread the docs on https://en.cppreference.com/w/cpp/error/runtime_error. The declaration does not show the base class, only the Inheritance diagram does.