Git/Hg SubmitEditor: Fix buttons in confirmation dialog for close

Don't show the "cancel" button.

Task-number: QTCREATORBUG-10451
Change-Id: I904794460ef15562eb8db630d33b8a2443b036eb
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>

src/plugins/vcsbase/vcsbasesubmiteditor.cpp

@@ -579,8 +579,13 @@ VcsBaseSubmitEditor::PromptSubmitResult
         }
     } else {
         // Check failed.
+        QMessageBox::StandardButtons buttons;
+        if (canCommitOnFailure)
+            buttons = QMessageBox::Yes|QMessageBox::No|QMessageBox::Cancel;
+        else
+            buttons = QMessageBox::Yes|QMessageBox::No;
         QMessageBox msgBox(QMessageBox::Question, title, checkFailureQuestion,
-                           QMessageBox::Yes|QMessageBox::No|QMessageBox::Cancel, parent);
+                           buttons, parent);
         msgBox.setDefaultButton(QMessageBox::Cancel);
         msgBox.setInformativeText(errorMessage);
         msgBox.setMinimumWidth(checkDialogMinimumWidth);