Unregister shutdown hook when tracer is closed

[TomasHofman]

Resolves #677

Signed-off-by: Tomas Hofman thofman@redhat.com

Which problem is this PR solving?

• Avoid memory leak in JaegerTracer.

Short description of the changes

• Unregister the shutdown hook when tracer is closed. (The hook is registered during tracer instance creation.)

[codecov]

Codecov Report

Merging #679 into master will increase coverage by 0.15%.
The diff coverage is 75%.

@@             Coverage Diff              @@
##             master     #679      +/-   ##
============================================
+ Coverage     89.59%   89.75%   +0.15%     
- Complexity      567      570       +3     
============================================
  Files            69       69              
  Lines          2086     2089       +3     
  Branches        266      267       +1     
============================================
+ Hits           1869     1875       +6     
+ Misses          135      133       -2     
+ Partials         82       81       -1

Impacted Files	Coverage Δ	Complexity Δ
...n/java/io/jaegertracing/internal/JaegerTracer.java	88.01% <75%> (-0.92%)	26 <0> (ø)
...ing/internal/samplers/RemoteControlledSampler.java	92.5% <0%> (+1.25%)	17% <0%> (+1%)	⬆️
...gertracing/internal/reporters/LoggingReporter.java	90.9% <0%> (+9.09%)	5% <0%> (+1%)	⬆️
...rtracing/internal/reporters/CompositeReporter.java	100% <0%> (+28.57%)	7% <0%> (+1%)	⬆️

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[pavolloffay]

@TomasHofman do you also need this fix in version 0.34.0?

[TomasHofman]

@TomasHofman do you also need this fix in version 0.34.0?

That would be ideal, that's the version we are using in Wildfly.