Don't run coveralls for flake8

Author: sjagoe

.travis.yml

@@ -68,6 +68,9 @@ notifications:
     - [email protected]
 
 after_success:
-  - if [[ $TRAVIS_PYTHON_VERSION == '2.6' ]]; then pip install "idna < 2.8"; fi
-  - pip install coveralls
-  - coveralls
+  - |
+    if [[ "$TOXENV" != "flake8" ]]; then
+      if [[ "$TRAVIS_PYTHON_VERSION" == "2.6" ]]; then pip install "idna < 2.8"; fi
+      pip install coveralls
+      coveralls
+    fi