Register client and add first test

Add first API test and register the client with
the new tempest.lib client interface.

Change-Id: I27f15375c46faa48cd56c8d52ecfd585fb325239
Implements: bp tempest-plugin
diff --git a/requirements.txt b/requirements.txt
index 16d3d08..415ded0 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -6,3 +6,4 @@
 
 tempest>=12.1.0  # Apache-2.0
 tempest-lib>=0.14.0  # Apache-2.0
+cryptography!=1.3.0,>=1.0 # BSD/Apache-2.0