Remove old Travis CI config

We are using Github Actions now, so remove the unused Travis CI
configuration file.

Signed-off-by: Patrick McCarty <patrick.mccarty@intel.com>

.travis.yml

@@ -1,17 +0,0 @@
-language: python
-dist: xenial
-sudo: enabled
-python:
-  - "3.6"
-
-before_install:
-  - sudo apt-get update
-  - sudo apt-get install -y libgnutls-dev
-
-install:
-  - pip install -r requirements.txt
-
-# command to run tests
-script:
-  - make check
-  - make unittests