remove a redundant error check

[ebi-yade]

Hi there,

Thanks for this excellent implementation of QUIC in GO; I'm a beginner at learning it!

This is just a tiny fix, but according to a suggestion by an IDE, the nil checking of the err variable is actually unnecessary here 👀

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[ebi-yade]

@googlebot I signed it!

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[codecov]

Codecov Report

Merging #3210 (f767474) into master (a887f8f) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #3210   +/-   ##
=======================================
  Coverage   85.40%   85.40%           
=======================================
  Files         134      134           
  Lines        9825     9825           
=======================================
  Hits         8391     8391           
  Misses       1060     1060           
  Partials      374      374           

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[marten-seemann]

Thank you!