Avoid duplicate rev= parameters for Delete() method

[flimzy]

Backport of #266

[codecov]

Codecov Report

Merging #267 (422cfbc) into v3 (487ff2f) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##               v3     #267   +/-   ##
=======================================
  Coverage   88.96%   88.96%           
=======================================
  Files          31       31           
  Lines        2002     2003    +1     
=======================================
+ Hits         1781     1782    +1     
  Misses        157      157           
  Partials       64       64           

Impacted Files	Coverage Δ
chttp/chttp.go	94.75% <ø> (ø)
db.go	80.43% <100.00%> (+0.03%)	⬆️

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