Display RingID during account migration

During the account migration of a Beta 1 account we are showing the
accountId instead of the RingID. It is not usefull to the user at all,
but the RingID is.

Change-Id: I4cde0fa74491f21371b04251a41d9fd291887dd7
Tuleap: #1184
diff --git a/src/MigrateRingAccountsWC.mm b/src/MigrateRingAccountsWC.mm
index 0e49e11..98cf9bc 100644
--- a/src/MigrateRingAccountsWC.mm
+++ b/src/MigrateRingAccountsWC.mm
@@ -81,8 +81,8 @@
                             };
     [infoMessage appendAttributedString:[[NSAttributedString alloc] initWithString:self.account->alias().toNSString() attributes:attrs]];
     [infoMessage appendAttributedString:[[NSAttributedString alloc] initWithString:@"\n"]];
-    [infoMessage appendAttributedString:[[NSAttributedString alloc] initWithString:NSLocalizedString(@"ID : ",@"Text shown to the user")]];
-    [infoMessage appendAttributedString:[[NSAttributedString alloc] initWithString:@(self.account->id().constData()) attributes:attrs]];
+    [infoMessage appendAttributedString:[[NSAttributedString alloc] initWithString:NSLocalizedString(@"RingID : ",@"Text shown to the user")]];
+    [infoMessage appendAttributedString:[[NSAttributedString alloc] initWithString:self.account->username().toNSString() attributes:attrs]];
     [infoMessage appendAttributedString:[[NSAttributedString alloc] initWithString:@"\n"]];
     [infoMessage appendAttributedString:[[NSAttributedString alloc] initWithString:NSLocalizedString(@"To proceed with the migration, you must choose a password for your account. This password will be used to encrypt your master key. It will be required for adding new devices to your Ring account. If you are not ready to choose a password, you may close Ring and resume the migration later.",@"Text shown to the user")]];
     [infoField setAttributedStringValue:infoMessage];