Fix Travis deployment

.travis.yml

@@ -10,6 +10,10 @@ install:
 script:
   - docker-compose run tests
 
+before_deploy:
+- sudo pip install twine
+- sudo pip install urllib3[secure]
+
 deploy:
   provider: pypi
   user: noplay

gns3server/version.py

@@ -23,7 +23,7 @@
 # or negative for a release candidate or beta (after the base version
 # number has been incremented)
 
-__version__ = "2.1.0dev9"
+__version__ = "2.1.0rc3"
 __version_info__ = (2, 1, 0, -99)
 
 # If it's a git checkout try to add the commit