Merge pull request #4350 from blueyed/fix-macos-py37

Travis: fix MacOS py37 build

Author: blueyed

.travis.yml

@@ -47,11 +47,6 @@ jobs:
       env: TOXENV=py37
       before_install:
         - brew update
-        # remove c++ include files because upgrading python as of 2018-10-23, also
-        # attempts to upgrade gcc, and it fails because the include files already
-        # exist. removing the include files is one of the solutions recommended by brew
-        # this workaround might not be necessary in the future
-        - rm '/usr/local/include/c++'
         - brew upgrade python
         - brew unlink python
         - brew link python