[travis] Install everything but mypy from requirements on Py 2.7

.travis.yml

@@ -5,7 +5,7 @@ python:
   - "3.5"
   - "3.6"
 install:
-  - if test `python --version 2>&1 | cut -d " " -f 2 | cut -d "." -f 1`  = 3; then pip install -r requirements.txt; else pip install asserts==0.8.0; fi
+  - if test `python --version 2>&1 | cut -d " " -f 2 | cut -d "." -f 1`  = 3; then pip install -r requirements.txt; else pip install `grep -v mypy requirements.txt`; fi
 script:
   - python -m unittest discover -t . -s test_htmlgen -p "*.py"
   - if test `python --version 2>&1 | cut -d " " -f 2 | cut -d "." -f 1`  = 3; then mypy htmlgen test_htmlgen; fi