fix spurious logging issue

[Zsailer]

This fixes the issue we've been seeing in JupyterLab with spurious logging.

See @ellisonbg's image originally posted in jupyter-server/jupyter_server#272.

[blink1073]

Thanks!

[Zsailer]

Oops, fixing the tests now. I ran them locally on the wrong branch. sorry for the spam here.

[codecov-commenter]

Codecov Report

Merging #115 into master will decrease coverage by 0.17%.
The diff coverage is 85.71%.

@@            Coverage Diff             @@
##           master     #115      +/-   ##
==========================================
- Coverage   60.63%   60.46%   -0.18%     
==========================================
  Files          19       19              
  Lines        1504     1505       +1     
==========================================
- Hits          912      910       -2     
- Misses        592      595       +3     

Impacted Files	Coverage Δ
jupyterlab_server/settings_handler.py	73.93% <85.71%> (-1.31%)	⬇️

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[Zsailer]

Ok, fixed!

[blink1073]

Thanks!

[echarles]

Thx @Zsailer