Crossdock crash fix

[isaachier]

Fix #225

[codecov]

Codecov Report

Merging #228 into master will not change coverage.
The diff coverage is 50%.

@@           Coverage Diff           @@
##           master     #228   +/-   ##
=======================================
  Coverage   81.99%   81.99%           
=======================================
  Files          51       51           
  Lines        3226     3226           
=======================================
  Hits         2645     2645           
  Misses        457      457           
  Partials      124      124

Impacted Files	Coverage Δ
crossdock/client/trace.go	66.96% <50%> (ø)	⬆️

---

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 7b337ce...9b7a475. Read the comment docs.

[yurishkuro]

could you squash and rebase from master? Not clear what's up with code coverage.

[isaachier]

There are still panics with this fix. I think this might be related to jaegertracing/jaeger-idl#35, because my hand-fixed C++ thrift doesn't seem to conform with the input/output expected in the generated Go code. Unless you believe this is significant, I'm going to close this for now.