Fix IsErrPullClosed

[lunny]

As title.

[codecov-io]

Codecov Report

Merging #10093 into master will increase coverage by <.01%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master   #10093      +/-   ##
==========================================
+ Coverage   43.44%   43.45%   +<.01%     
==========================================
  Files         566      566              
  Lines       78987    78987              
==========================================
+ Hits        34318    34322       +4     
+ Misses      40432    40427       -5     
- Partials     4237     4238       +1

Impacted Files	Coverage Δ
services/pull/pull.go	33.93% <0%> (ø)	⬆️
services/pull/patch.go	64.77% <0%> (-3.15%)	⬇️
models/repo.go	51.46% <0%> (+0.13%)	⬆️
modules/log/event.go	65.64% <0%> (+1.02%)	⬆️
models/unit.go	39.5% <0%> (+2.46%)	⬆️
modules/process/manager.go	78.31% <0%> (+3.61%)	⬆️

---

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 8d43563...dead55b. Read the comment docs.

[bagasme]

Simply change the method?