minor: remove obsolete comment [ci skip]

Author: blueyed

.travis.yml

@@ -20,9 +20,6 @@ jobs:
   include:
     # OSX tests - first (in test stage), since they are the slower ones.
     - &test-macos
-      # NOTE: (tests with) pexpect appear to be buggy on Travis,
-      #       at least with coverage.
-      #       Log: https://travis-ci.org/pytest-dev/pytest/jobs/500358864
       os: osx
       osx_image: xcode10.1
       language: generic