fix: unlock correct dht_friend

[sudden6]

Thanks @zugz for pointing out the bug.

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This change is 

[codecov]

Codecov Report

Merging #2327 (306693a) into master (32ed67c) will decrease coverage by 0.02%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #2327      +/-   ##
==========================================
- Coverage   78.93%   78.91%   -0.03%     
==========================================
  Files         127      127              
  Lines       24078    24078              
==========================================
- Hits        19007    19002       -5     
- Misses       5071     5076       +5     

Impacted Files	Coverage Δ
toxcore/DHT.c	83.78% <100.00%> (-0.08%)	⬇️
toxcore/friend_connection.c	82.83% <0.00%> (-1.40%)	⬇️
toxav/groupav.c	73.91% <0.00%> (-0.67%)	⬇️
toxav/toxav.c	69.08% <0.00%> (-0.30%)	⬇️
toxcore/TCP_server.c	78.39% <0.00%> (-0.19%)	⬇️
toxcore/group.c	84.48% <0.00%> (+0.06%)	⬆️
toxcore/net_crypto.c	87.36% <0.00%> (+0.07%)	⬆️
toxcore/onion.c	85.79% <0.00%> (+0.28%)	⬆️
toxcore/TCP_connection.c	69.45% <0.00%> (+0.28%)	⬆️
... and 2 more

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