Print username instead of accountname when asking for password

When asking for a password interactively, the username is never
displayed which may hide problems (typos on the configuration, or
issues on offlineimap parsing of the config file).  The hostname,
port, and account name are already displayed when establishing the
connection.  When asking for password, the account name is displayed
again.  Change it to display the username.

Github-ref: https://github.com/OfflineIMAP/offlineimap/issues/558
Signed-off-by: David Miguel Susano Pinto <carandraug+dev@gmail.com>
Signed-off-by: Nicolas Sebrecht <nicolas.s-dev@laposte.net>

offlineimap/imapserver.py

@@ -175,8 +175,7 @@ class IMAPServer(object):
 
         # get 1) configured password first 2) fall back to asking via UI
         self.password = self.repos.getpassword() or \
-            self.ui.getpass(self.repos.getname(), self.config,
-                self.passworderror)
+            self.ui.getpass(self.username, self.config, self.passworderror)
         self.passworderror = None
         return self.password