VcsCommand: Block auto reload while a command is running

Git rebase is executed in the background, and it can change a file multiple
times in a short period. If we reparse a file while this happens on
Windows, Git fails to replace it, the rebase action fails and the
repository becomes unstable (remains with a modified file).

See discussion at https://github.com/git-for-windows/git/pull/1666

Task-number: QTCREATORBUG-15449
Change-Id: Iba40a770a1df2dfff0dd1c874c491dfbe1cceb58
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/coreplugin/documentmanager.h

@@ -69,6 +69,8 @@ public:
     static void expectFileChange(const QString &fileName);
     static void unexpectFileChange(const QString &fileName);
 
+    static void setAutoReloadPostponed(bool enabled);
+
     // recent files
     static void addToRecentFiles(const QString &fileName, Id editorId = Id());
     Q_SLOT void clearRecentFiles();