[git] Fix method signature

setLastSuccessful doesn't return any interesting value,
and it is never used => make it void.

plugins/git4idea/rt/src/org/jetbrains/git4idea/ssh/GitSSHHandler.java

@@ -124,7 +124,7 @@ public interface GitSSHHandler {
    * @param method    the authentication method, the empty string means that authentication failed
    * @param error     the error shown in the case when authentication process failed
    */
-  String setLastSuccessful(final int handlerNo, final String userName, final String method, final String error);
+  void setLastSuccessful(final int handlerNo, final String userName, final String method, final String error);
 
   /**
    * Get last successful authentication method

plugins/git4idea/rt/src/org/jetbrains/git4idea/ssh/GitSSHXmlRpcClient.java

@@ -182,9 +182,9 @@ public class GitSSHXmlRpcClient implements GitSSHHandler {
    */
   @Override
   @SuppressWarnings("unchecked")
-  public String setLastSuccessful(int handlerNo, String userName, String method, String error) {
+  public void setLastSuccessful(int handlerNo, String userName, String method, String error) {
     if (myClient == null) {
-      return "";
+      return;
     }
     Vector parameters = new Vector();
     parameters.add(handlerNo);
@@ -192,7 +192,7 @@ public class GitSSHXmlRpcClient implements GitSSHHandler {
     parameters.add(method);
     parameters.add(error);
     try {
-      return (String)myClient.execute(methodName("setLastSuccessful"), parameters);
+      myClient.execute(methodName("setLastSuccessful"), parameters);
     }
     catch (XmlRpcException e) {
       throw new RuntimeException("Invocation failed " + e.getMessage(), e);

plugins/git4idea/src/org/jetbrains/git4idea/ssh/GitXmlRpcSshService.java

@@ -86,9 +86,8 @@ public class GitXmlRpcSshService extends GitXmlRpcHandlerService<GitSSHGUIHandle
     }
 
     @Override
-    public String setLastSuccessful(int handlerNo, String userName, String method, String error) {
+    public void setLastSuccessful(int handlerNo, String userName, String method, String error) {
       getHandler(handlerNo).setLastSuccessful(userName, method, error);
-      return "";
     }
 
     @Override