fix doctest calling configLogger causing flakiness of other tests
fix doctest calling configLogger causing flakiness of other tests

since we use pytest-randomly to randomize the test execution, depending on when
this specific test is executed, it may have the side effect of configuring
the global logging configuration, causing other tests that capture logging
messages to fail.

E.g. see https://travis-ci.org/fonttools/fonttools/jobs/545680550

googlefonts/fonttools,fonttools/fonttools