Fix wrong DNS query type in DANE lookups for IPv6-only hosts

[cuihaoleo]

An apparent typo. This should fix #631.

The patch is tested on top of v0.7.

[codecov-commenter]

Codecov Report

Merging #632 (5d8f09e) into master (d9920f0) will increase coverage by 0.03%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##           master     #632      +/-   ##
==========================================
+ Coverage   52.39%   52.42%   +0.03%     
==========================================
  Files         128      128              
  Lines       13287    13287              
==========================================
+ Hits         6962     6966       +4     
+ Misses       5669     5666       -3     
+ Partials      656      655       -1     

Flag	Coverage Δ
integration	34.03% <ø> (ø)
unit	53.84% <0.00%> (+0.04%)	⬆️

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Files	Coverage Δ
framework/dns/dnssec.go	28.07% <0.00%> (ø)

... and 1 file with indirect coverage changes

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[foxcpp]

Thanks!