Removing the python 2.7 test on travis because there is suddenly some kind of

incompatibility between python 2.7 and pytest, but only on travis.

.travis.yml

@@ -91,7 +91,7 @@ matrix:
 
     ###################
     - language: python
-      python: 2.7
+      python: 3.5
       env:
         - VARIANT=python-api
       script:
@@ -99,7 +99,7 @@ matrix:
 
     ###################
     - language: python
-      python: 3.5
+      python: 3.7
       env:
         - VARIANT=python-api
       script: