rec: fix coverity 1564914 (afaiks harmless)

[omoerbeek]

Short description

The coverity report is about zoneIdx, but it is always initialized in rec-main.cc before being used. Still having no initialized fields is better in general.

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 11774792569

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 28 unchanged lines in 11 files lost coverage.
• Overall coverage remained the same at 64.659%

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Files with Coverage Reduction	New Missed Lines	%
pdns/packethandler.cc	1	72.57%
modules/gpgsqlbackend/gpgsqlbackend.cc	1	88.62%
pdns/recursordist/syncres.cc	1	79.55%
modules/lmdbbackend/lmdbbackend.cc	2	73.45%
pdns/misc.cc	2	63.49%
pdns/iputils.cc	3	54.99%
pdns/recursordist/test-syncres_cc2.cc	3	88.85%
pdns/backends/gsql/gsqlbackend.hh	3	96.57%
pdns/remote_logger.cc	3	53.81%
pdns/recursordist/rec-tcp.cc	4	64.63%

Totals
Change from base Build 11737481821:	0.0%
Covered Lines:	125719
Relevant Lines:	163585

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💛 - Coveralls