Move pysaml to requirements.txt for py3

pysaml is used by a required extension now.

Change-Id: I996a1c5ebb0876c5badf2541877a9a8166ab7240

requirements-py3.txt

@@ -31,6 +31,7 @@ oslo.policy>=0.3.0  # Apache-2.0
 oslo.serialization>=1.2.0               # Apache-2.0
 oslo.utils>=1.2.0                       # Apache-2.0
 oauthlib>=0.6
+pysaml2
 dogpile.cache>=0.5.3
 jsonschema>=2.0.0,<3.0.0
 # pycadf tries to pull in eventlet

test-requirements-py3.txt

@@ -23,10 +23,6 @@ pymongo>=2.5
 # ldappool>=1.0 # MPL
 -e git+https://github.com/rbarrois/python-ldap.git@py3#egg=python-ldap
 
-# Required for federation extension (although used only for federating multiple
-# Keystones)
-pysaml2
-
 # Testing
 # computes code coverage percentages
 coverage>=3.6