Make sure tracing is only enabled in debug mode

[kostko]

No description provided.

[codecov]

Codecov Report

Merging #3679 (285ece0) into master (789751c) will decrease coverage by 0.01%.
The diff coverage is 66.66%.

@@            Coverage Diff             @@
##           master    #3679      +/-   ##
==========================================
- Coverage   66.70%   66.68%   -0.02%     
==========================================
  Files         393      393              
  Lines       38367    38370       +3     
==========================================
- Hits        25592    25588       -4     
+ Misses       9102     9098       -4     
- Partials     3673     3684      +11     

Impacted Files	Coverage Δ
go/oasis-node/cmd/common/tracing/tracing.go	66.66% <33.33%> (-4.31%)	⬇️
go/worker/common/committee/group.go	74.42% <50.00%> (-1.83%)	⬇️
go/common/grpc/grpc.go	84.89% <100.00%> (-0.29%)	⬇️
go/oasis-node/cmd/common/metrics/disk.go	65.38% <0.00%> (-19.24%)	⬇️
go/oasis-node/cmd/common/metrics/resource.go	78.94% <0.00%> (-10.53%)	⬇️
go/common/grpc/policy/policy.go	62.12% <0.00%> (-7.58%)	⬇️
go/consensus/tendermint/full/services.go	80.00% <0.00%> (-4.17%)	⬇️
go/worker/keymanager/worker.go	61.06% <0.00%> (-2.81%)	⬇️
.../consensus/tendermint/apps/roothash/state/state.go	71.25% <0.00%> (-2.50%)	⬇️
go/runtime/host/protocol/connection.go	57.55% <0.00%> (-2.45%)	⬇️
... and 23 more

---

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 789751c...285ece0. Read the comment docs.