Use falcon from pip instead of apt for Travis

.travis.yml

@@ -10,7 +10,7 @@ virtualenv:
 install:
   - pip install -r requirements.txt
   - pip install --editable .
-  - pip install codecov pytest-cov click ipaddress humanize
+  - pip install codecov pytest-cov click ipaddress humanize falcon
 script:
   - py.test --cov-report xml --cov=certidude tests/
 cache:
@@ -21,7 +21,6 @@ addons:
     packages:
     - python-xattr
     - python-setproctitle
-    - python-falcon
     - python-markdown
     - python-jinja2
     - python-configparser