Ensure trace propagation in our logs.

[cyriltovena]

This ensure we log correctly the traceID when possible. Rest of the fixes is in Cortex.

see cortexproject/cortex#2519 and cortexproject/cortex#2518

Signed-off-by: Cyril Tovena cyril.tovena@gmail.com

[slim-bean]

LGTM!

[codecov-io]

Codecov Report

Merging #1977 into master will increase coverage by 0.18%.
The diff coverage is 59.04%.

@@            Coverage Diff             @@
##           master    #1977      +/-   ##
==========================================
+ Coverage   64.28%   64.46%   +0.18%     
==========================================
  Files         131      131              
  Lines       10017    10038      +21     
==========================================
+ Hits         6439     6471      +32     
+ Misses       3095     3084      -11     
  Partials      483      483              

Impacted Files	Coverage Δ
pkg/ingester/tailer.go	38.01% <0.00%> (ø)
pkg/logcli/query/query.go	0.00% <0.00%> (ø)
pkg/logql/evaluator.go	91.27% <ø> (ø)
pkg/loki/modules.go	15.78% <0.00%> (ø)
pkg/querier/http.go	10.14% <0.00%> (-0.05%)	⬇️
pkg/querier/queryrange/stats.go	82.75% <0.00%> (ø)
pkg/storage/iterator.go	84.44% <0.00%> (ø)
pkg/storage/stores/local/shipper.go	53.22% <0.00%> (-0.44%)	⬇️
pkg/loghttp/query.go	40.70% <20.00%> (-0.96%)	⬇️
pkg/querier/tail.go	67.64% <33.33%> (+0.23%)	⬆️
... and 11 more