[gitg] Fix credentials signature

[Jesse van den Kieboom <jessevdk src gnome org>]

commit 5c1bb0116808cf108703264ed4442800dd02651b
Author: Jesse van den Kieboom <jessevdk gmail com>
Date:   Wed Dec 24 10:02:01 2014 +0100

    Fix credentials signature

 gitg/gitg-remote-manager.vala |   15 ++++++---------
 1 files changed, 6 insertions(+), 9 deletions(-)
---
diff --git a/gitg/gitg-remote-manager.vala b/gitg/gitg-remote-manager.vala
index ed67160..a7d1a09 100644
--- a/gitg/gitg-remote-manager.vala
+++ b/gitg/gitg-remote-manager.vala
@@ -48,27 +48,24 @@ class RemoteManager : Object, GitgExt.RemoteLookup
                        d_window = window;
                }
 
-               protected override bool credentials(string        url,
-                                                   string        username,
-                                                   Ggit.Credtype allowed_types,
-                                                   out Ggit.Cred cred) throws Error
+               protected override Ggit.Cred? credentials(string        url,
+                                                         string?       username,
+                                                         Ggit.Credtype allowed_types) throws Error
                {
-                       cred = null;
-
                        if ((allowed_types & Ggit.Credtype.SSH_KEY) != 0)
                        {
-                               cred = new Ggit.CredSshKeyFromAgent(username);
+                               return new Ggit.CredSshKeyFromAgent(username);
                        }
                        else if ((allowed_types & Ggit.Credtype.SSH_INTERACTIVE) != 0)
                        {
-                               cred = new CredSshInteractive(username);
+                               return new CredSshInteractive(username);
                        }
                        else if ((allowed_types & Ggit.Credtype.USERPASS_PLAINTEXT) != 0)
                        {
                                // TODO: query for user + pass
                        }
 
-                       return cred != null;
+                       return null;
                }
        }