fix tox norsa typo

Author: mattsb42-aws

tox.ini

@@ -26,7 +26,7 @@ commands_pre =
     # Remove the python-rsa and python-ecdsa backends
     only: pip uninstall -y ecdsa rsa
     # Remove just the python-rsa backend
-    nosra: pip uninstall -y rsa
+    norsa: pip uninstall -y rsa
 commands =
     # Test the python-rsa backend
     base: {[testenv:basecommand]commands} -m "not (cryptography or pycryptodome or pycrypto or backend_compatibility)"