Remove rsa restriction (#310)

* DO NOT MERGE: Testing travis

* Remove rsa restriction

* Remove unwanted comment
diff --git a/setup.py b/setup.py
index 2a5ac7a..ab1a50c 100644
--- a/setup.py
+++ b/setup.py
@@ -28,7 +28,6 @@
 # Configure the required packages and scripts to install, depending on
 # Python version and OS.
 REQUIRED_PACKAGES = [
-    'rsa<=4.0; python_version < "3.5"',
     'httplib2>=0.8',
     'fasteners>=0.14',
     'oauth2client>=1.4.12',