ONOS-6020 RolledBack and deprecated a method in NetconfDeviceInfo to not break backwards compatibility

Change-Id: Ie029f6b1d3688d428130b76ed2e06c760d9a390a
diff --git a/protocols/netconf/ctl/src/main/java/org/onosproject/netconf/ctl/NetconfSessionImpl.java b/protocols/netconf/ctl/src/main/java/org/onosproject/netconf/ctl/NetconfSessionImpl.java
index 451a2a1..26ded2f 100644
--- a/protocols/netconf/ctl/src/main/java/org/onosproject/netconf/ctl/NetconfSessionImpl.java
+++ b/protocols/netconf/ctl/src/main/java/org/onosproject/netconf/ctl/NetconfSessionImpl.java
@@ -118,7 +118,13 @@
             }
             boolean isAuthenticated;
             try {
-                if (deviceInfo.getKey() != null) {
+                if (deviceInfo.getKeyFile() != null && deviceInfo.getKeyFile().canRead()) {
+                    log.debug("Authenticating with key file to device {} with username {}",
+                              deviceInfo.getDeviceId(), deviceInfo.name());
+                    isAuthenticated = netconfConnection.authenticateWithPublicKey(
+                            deviceInfo.name(), deviceInfo.getKeyFile(),
+                            deviceInfo.password().equals("") ? null : deviceInfo.password());
+                } else if (deviceInfo.getKey() != null) {
                     log.debug("Authenticating with key to device {} with username {}",
                             deviceInfo.getDeviceId(), deviceInfo.name());
                     isAuthenticated = netconfConnection.authenticateWithPublicKey(