refactor: close connection on error

[pedrokiefer]

Port the solution from PyMySQL: PyMySQL/PyMySQL#540

Might solve #340.

[codecov]

Codecov Report

Merging #358 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #358   +/-   ##
=======================================
  Coverage   93.17%   93.17%           
=======================================
  Files           9        9           
  Lines        1129     1129           
  Branches      161      161           
=======================================
  Hits         1052     1052           
  Misses         54       54           
  Partials       23       23           

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[terricain]

Any clue why the tests failed for py3.5.3?

[terricain]

Other than that the tests and port looks good. Have you tested it normally by having it connected to a maria db, restarting it and seeing if the close packets are now understood?

[pedrokiefer]

Really odd that it failed with python 3.5.3, i'll look into it.

I have not yet tested this against mariadb, i'll do a simple script to replicate the scenario and test it tomorrow.

[goDeni]

Please merge this

[CLAassistant]

All committers have signed the CLA.

[Nothing4You]

thanks for the PR, I intend to patch the original issue in #660.
I'm keeping this open to review the tests later on.

[pedrokiefer]

Thanks for fixing this issue!

[Nothing4You]

i'll keep this open for now until i've had time to review and probably merge the tests