Fix mem leak

[JShep1]

Fixing a small memory leak that I came across while profiling ign-gazebo. Not sure if sock needs to be closed before that return call though, but since it was being done at the end of the function, I added it before the error-out return call as well.

[codecov]

Codecov Report

Merging #174 into ign-transport8 will decrease coverage by 0.43%.
The diff coverage is 0.00%.

@@                Coverage Diff                 @@
##           ign-transport8     #174      +/-   ##
==================================================
- Coverage           83.84%   83.41%   -0.44%     
==================================================
  Files                  49       49              
  Lines                5058     4920     -138     
==================================================
- Hits                 4241     4104     -137     
+ Misses                817      816       -1     

Impacted Files	Coverage Δ
src/NodeShared.cc	77.95% <0.00%> (-0.31%)	⬇️
log/src/Playback.cc	93.51% <0.00%> (-1.28%)	⬇️

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[caguero]

Good catch! Looks good to me.