Recover middleware should not log panic for aborted handler (fix #2133)

[bbasic]

This is the fix for the issue #2133

The fix is in explicit check in recover middleware defer function to re-throw (panic) the http.ErrAbortHandler error.

This specific error is recovered in net/http/server.go and per default ignored for logging.
https://github.com/golang/go/blob/88be85f18bf0244a2470fdf6719e1b5ca5a5e50a/src/net/http/server.go#L1799

[codecov]

Codecov Report

Merging #2134 (7f2e32b) into master (b445958) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #2134   +/-   ##
=======================================
  Coverage   92.10%   92.11%           
=======================================
  Files          37       37           
  Lines        3028     3030    +2     
=======================================
+ Hits         2789     2791    +2     
  Misses        150      150           
  Partials       89       89           

Impacted Files	Coverage Δ
middleware/recover.go	85.00% <100.00%> (+0.78%)	⬆️

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[aldas]

LGTM

[aldas]

@lammel please review

[lammel]

Also looks good to me.
I think an end2end test is nice to have, but not really required, so let's merge.