auth: minor getAllDomains optimizations

[miodvallat]

Short description

A few backends were nevertheless fetching the SOA record in getAllDomains, even if the caller did not ask for serial numbers.

Checklist

I have:

• read the CONTRIBUTING.md document
• read and accepted the Developer Certificate of Origin document, including the AI Policy, and added a "Signed-off-by" to my commits
• 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 19764495151

Details

• 6 of 12 (50.0%) changed or added relevant lines in 2 files are covered.
• 42 unchanged lines in 8 files lost coverage.
• Overall coverage decreased (-0.01%) to 73.092%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
modules/lmdbbackend/lmdbbackend.cc	5	7	71.43%
modules/geoipbackend/geoipbackend.cc	1	5	20.0%

Files with Coverage Reduction	New Missed Lines	%
pdns/dnsdistdist/dnsdist-tcp.cc	1	77.7%
pdns/recursordist/rec-main.cc	2	64.79%
pdns/recursordist/rec-tcpout.cc	2	79.53%
pdns/recursordist/rec-xfr.cc	2	73.94%
pdns/axfr-retriever.cc	3	66.94%
modules/godbcbackend/sodbc.cc	6	70.08%
pdns/recursordist/syncres.cc	7	80.97%
pdns/recursordist/rec-system-resolve.cc	19	45.92%

Totals
Change from base Build 19741851688:	-0.01%
Covered Lines:	128092
Relevant Lines:	164538

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💛 - Coveralls