backupninja metadata fix

Change-Id: I35093e7768037c25bb77d5316515e8f18d2c7d85
diff --git a/metadata/service/server/single.yml b/metadata/service/server/single.yml
index c502830..47800d3 100644
--- a/metadata/service/server/single.yml
+++ b/metadata/service/server/single.yml
@@ -1,6 +1,13 @@
 applications:
 - backupninja
 parameters:
+  _param:
+    backupninja_public_key: ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQCzLUiHKAjfFXiZ3fsgx35uXF6VivfC5WFafu4QMalxmj6W+s277oCfdWA8Du5f1wtQXM73VQ5nHkXhM2UIfUMarsyhXK+BxKVrcgEBNHdKlDytaecUPyuOxTDdGWhN/DPv5/vL8NYWweEYBbNbLgU0Td7Rvm52TUXKThIDjeF7XDxX4ShXWipBSwU4boOUBtR8KWfga8fsqeBN+eacuAQFR3MrrOfVvAuWW6Bsf047cmd+V6Qv0raoW73Nu4M/ZAdTsaR5k62a0cHsSRoi3hCmNRqw+CZaQi8prQU6t26eWPEtznjp5EkPF+LLh8LxUoCfWqWT+Lxe8QQwT1nx/LCN
   backupninja:
     server:
       enabled: true
+      rdiff: true
+      key:
+        backupninja_pub_key:
+          enabled: true
+          key: ${_param:backupninja_public_key}