Fixes list of requirements

Please see the following link for more detailed information:
https://github.com/openstack/requirements/blob/master/global-requirements.txt

Change-Id: I2fae60646c56f29d4d8238356553b667b787f6cc

requirements.txt

@@ -1,18 +1,18 @@
-pbr>=0.5.21,<1.0
+pbr>=0.6,!=0.7,<1.0
 eventlet>=0.13.0
-pyyaml
-pecan>=0.2.0
-WSME>=0.5b6
+PyYAML>=3.1.0
+pecan>=0.4.5
+WSME>=0.6
 amqplib>=0.6.1
 argparse
-croniter
-requests
+croniter>=0.3.4 # MIT License
+requests>=1.1
 kombu>=2.4.8
 oslo.config>=1.2.0
-oslo.messaging>=1.3.0a4
+oslo.messaging>=1.3.0
 paramiko>=1.9.0
-python-keystoneclient>=0.3.2
-networkx
-six>=1.5.2
-SQLAlchemy
-yaql==0.2.1
+python-keystoneclient>=0.7.0
+networkx>=1.8
+six>=1.6.0
+SQLAlchemy>=0.7.8,<=0.9.99
+yaql==0.2.1 # This is not in global requirements