Fixed Jaeger GRPC exporter

[owais]

The exporter was essentially crashing itself unconditionally

[flands]

LGTM

[bogdandrutu]

:) good tests for this.

[owais]

Travis build is failing for an unrelated reason. Looks like it can't pull in some dependencies. I tried building locally even after wiping all of my Go modules cache and it worked without any issues.

CI error:

go: git.apache.org/thrift.git@v0.0.0-20180902110319-2566ecd5d999: git fetch -f origin refs/heads/*:refs/heads/* refs/tags/*:refs/tags/* in /home/travis/gopath/pkg/mod/cache/vcs/83dba939f95a790e497d565fc4418400145a1a514f955fa052f662d56e920c3e: exit status 128:

	fatal: unable to access 'https://git.apache.org/thrift.git/': Failed to connect to git.apache.org port 443: Connection timed out

go: error loading module requirements

go install golang.org/x/lint/golint

go: finding git.apache.org/thrift.git v0.0.0-20180902110319-2566ecd5d999

go: git.apache.org/thrift.git@v0.0.0-20180902110319-2566ecd5d999: git fetch -f https://git.apache.org/thrift.git refs/heads/*:refs/heads/* refs/tags/*:refs/tags/* in /home/travis/gopath/pkg/mod/cache/vcs/83dba939f95a790e497d565fc4418400145a1a514f955fa052f662d56e920c3e: exit status 128:

	fatal: unable to access 'https://git.apache.org/thrift.git/': Failed to connect to git.apache.org port 443: Connection timed out

go: error loading module requirements

Makefile:82: recipe for target 'install-tools' failed

make: *** [install-tools] Error 1

[codecov]

Codecov Report

Merging #622 into master will decrease coverage by 0.01%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master     #622      +/-   ##
==========================================
- Coverage   69.35%   69.34%   -0.02%     
==========================================
  Files          93       93              
  Lines        6157     6158       +1     
==========================================
  Hits         4270     4270              
- Misses       1660     1661       +1     
  Partials      227      227

Impacted Files	Coverage Δ
...occollector/app/sender/jaeger_proto_grpc_sender.go	0% <0%> (ø)	⬆️

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[owais]

The repo was moved to github. Adding a replace directive fixed the build. https://github.com/census-instrumentation/opencensus-service/pull/622/files#diff-37aff102a57d3d7b797f152915a6dc16R63