fix for backward compatibility for old reclass model definition with new salt 2017xx (#9)

* if ssh user is disabled, then remove authorized_keys

* fix for backward compatibility with old model in new salt 2017xx

* fix previous merge

* fix example in Readme

* added md5 as default if not present

* merge with upstream
diff --git a/README.rst b/README.rst
index b82a36b..2cf834b 100644
--- a/README.rst
+++ b/README.rst
@@ -40,6 +40,7 @@
             - name: repo.domain.com
               type: rsa
               fingerprint: dd:fa:e8:68:b1:ea:ea:a0:63:f1:5a:55:48:e1:7e:37
+              fingerprint_hash_type: sha256|md5
 
 Configure keep alive settings: