ci: Add travis build step for Python 2.7 tests

Signed-off-by: Nabarun Pal <pal.nabarun95@gmail.com>

Author: palnabarun

.travis.yml

@@ -21,6 +21,7 @@ jobs:
     # Basic Checks
     - stage: primary
       env: NOXSESSION=lint-3.5
+    - env: NOXSESSION=test-2.7
     - env: NOXSESSION=test-3.5
     - env: NOXSESSION=docs