VcsCommand: Limit the usage of setCookie()

Don't use setCookie() for setting the line number
to be shown on annotation. Add setDefaultLineNumber()
setter to VcsBaseEditorWidget instead.

Change-Id: I6c52874d48532132a27b2a7a9d161705170f7ade
Reviewed-by: Orgad Shaneh <orgads@gmail.com>

src/plugins/vcsbase/vcsbaseclient.cpp

@@ -375,7 +375,7 @@ VcsBaseEditorWidget *VcsBaseClient::annotate(
                                                   vcsCmdString.toLatin1().constData(), id);
 
     VcsCommand *cmd = createCommand(workingDir, editor);
-    cmd->setCookie(lineNumber);
+    editor->setDefaultLineNumber(lineNumber);
     enqueueJob(cmd, args);
     return editor;
 }