Revert "Add jsonschema to requirements.txt"

This reverts commit d35a64499673c2d765dd342fa21dabdbfa4ba276.

Which is possibly the cause of grenade failing the gate, we'll
bring this back later if it isn't.

Change-Id: I00815f7ef053ae4d5da71fa31885a52ae887c6fc
diff --git a/requirements.txt b/requirements.txt
index ee754dc..06aa9f3 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -3,7 +3,6 @@
 anyjson
 nose
 httplib2>=0.7.0
-jsonschema>=1.0.0,!=1.4.0,<2
 testtools>=0.9.32
 lxml
 boto>=2.2.1