Delete unused arg

[sashamelentyev]

This PR is sponsored by Evrone

[codecov]

Codecov Report

Merging #2834 (af4d74b) into master (f3a6b69) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #2834   +/-   ##
=======================================
  Coverage   98.75%   98.75%           
=======================================
  Files          41       41           
  Lines        3063     3063           
=======================================
  Hits         3025     3025           
  Misses         26       26           
  Partials       12       12           

Flag	Coverage Δ
go-1.13	98.75% <100.00%> (ø)
go-1.14	98.59% <100.00%> (ø)
go-1.15	98.59% <100.00%> (ø)
go-1.16	98.59% <100.00%> (ø)
macos-latest	98.75% <100.00%> (ø)
nomsgpack	98.74% <100.00%> (ø)
ubuntu-latest	98.75% <100.00%> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
binding/form_mapping.go	100.00% <100.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update f3a6b69...af4d74b. Read the comment docs.

[sashamelentyev]

@appleboy @thinkerou

[thinkerou]

lgtm