Fix MySQL extra definition

[k1LoW]

No description provided.

[codecov]

Codecov Report

Merging #272 (be78ff5) into master (ba329ef) will not change coverage.
The diff coverage is 50.00%.

@@           Coverage Diff           @@
##           master     #272   +/-   ##
=======================================
  Coverage   66.02%   66.02%           
=======================================
  Files          23       23           
  Lines        3979     3979           
=======================================
  Hits         2627     2627           
  Misses       1085     1085           
  Partials      267      267           

Impacted Files	Coverage Δ
drivers/mysql/mysql.go	73.85% <50.00%> (ø)

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