Prevent NULL account name

app/src/main/java/eu/faircode/email/FragmentOAuth.java

@@ -986,7 +986,10 @@ public class FragmentOAuth extends FragmentBase {
                         int at = account.user.indexOf('@');
                         String user = account.user.substring(0, at);
 
-                        account.name = provider.name + "/" + user;
+                        if (TextUtils.isEmpty(provider.name))
+                            account.name = account.user;
+                        else
+                            account.name = provider.name + "/" + user;
 
                         account.synchronize = true;
                         account.primary = (primary == null);

app/src/main/java/eu/faircode/email/FragmentQuickSetup.java

@@ -621,7 +621,10 @@ public class FragmentQuickSetup extends FragmentBase {
                                 account.password = password;
                                 account.fingerprint = imap_fingerprint;
 
-                                account.name = provider.name + "/" + username;
+                                if (TextUtils.isEmpty(provider.name))
+                                    account.name = email;
+                                else
+                                    account.name = provider.name + "/" + username;
 
                                 account.synchronize = true;
                                 account.primary = (primary == null);