Correct typo in .kitchen.yml

This change has no impact on the kitchen tests, but only changes
a symbolic name from 'openssl' to 'openssh' to avoid confusion.

.kitchen.yml

@@ -19,8 +19,8 @@ provisioner:
     top.sls:
       base:
         '*':
-          - openssl
-    openssl.sls:
+          - openssh
+    openssh.sls:
       openssh:
         sshd_config_mode: '600'