recovery: fix issue about syscall import on google app engine

[thinkerou]

cc @justinfx please help me review, thanks!

ref: https://github.com/golang/go/blob/master/src/syscall/zerrors_linux_amd64.go

[codecov]

Codecov Report

Merging #1640 into master will not change coverage.
The diff coverage is 100%.

@@           Coverage Diff           @@
##           master    #1640   +/-   ##
=======================================
  Coverage   99.29%   99.29%           
=======================================
  Files          40       40           
  Lines        1973     1973           
=======================================
  Hits         1959     1959           
  Misses         10       10           
  Partials        4        4

Impacted Files	Coverage Δ
recovery.go	100% <100%> (ø)	⬆️

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[justinfx]

I was reviewing before you added the Lower, and was about to make that same suggestion since I saw mixed case between different OS/arch. Good call!

[sublee]

Can it be merged?

[thinkerou]

@sublee need @appleboy review and merged, thanks!

[appleboy]

@justinfx @sublee merged.

[justinfx]

thanks!

[sublee]

Thank you!