VCS: Abort previous command for the same editor

It is very common to have output from a previous (longer) command appear
instead of the newly created one.

For example: Open a log. Check "Show Diff" and immediately uncheck it.
If this is done fast enough (or with a high Log Count limit) the output
with the diff will appear instead of the normal log.

Change-Id: Ie64cc4a383a261f5328a4d0486eec93f73766679
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>

src/plugins/vcsbase/vcsbaseclient.cpp

@@ -143,6 +143,7 @@ void VcsBaseClientPrivate::saveSettings()
 
 void VcsBaseClientPrivate::bindCommandToEditor(Command *cmd, VcsBaseEditorWidget *editor)
 {
+    editor->setCommand(cmd);
     QObject::connect(cmd, SIGNAL(finished(bool,int,QVariant)), m_cmdFinishedMapper, SLOT(map()));
     m_cmdFinishedMapper->setMapping(cmd, editor);
 }