Try to fix the xml syntax for coverage<4

Author: iMichka

.travis.yml

@@ -18,7 +18,7 @@ before_install:
   # Install coverage tools (On 3.2 the new coverage is broken, use an old one)
   # https://github.com/menegazzo/travispy/issues/20
   - if [ $TRAVIS_PYTHON_VERSION == 3.2 ];
-    then pip install coverage<4; else
+    then pip install 'coverage<4.0'; else
     pip install coverage;
     fi
   - pip install coveralls