change dependences in requirements.txt due to version conflict on debian. see also tokenserver:#219 (#277)

requirements.txt

@@ -1,14 +1,16 @@
-cornice==0.16.2
-gunicorn==19.6
-pyramid==1.5.3
-WebOb==1.4.1
-requests==2.20
+gevent==1.4.0
+greenlet==0.4.14
+cornice==3.5.1
+gunicorn==19.10.0
+pyramid==1.10.4
+WebOb==1.8.5
+requests==2.22.0
 SQLAlchemy==1.3.3
 unittest2==1.1
 zope.component==4.2.1
-configparser==3.5
-mozsvc==0.9
-futures==3.0
+configparser==3.7.4
+mozsvc==0.10
+futures==3.2
 soupsieve==1.9.5
 umemcache==1.6.3
 google-cloud-spanner==1.18.0