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/git/gitclient.cpp

@@ -1379,7 +1379,8 @@ VcsBaseEditorWidget *GitClient::annotate(
     arguments << argWidget->arguments() << "--" << file;
     if (!revision.isEmpty())
         arguments << revision;
-    vcsExec(workingDir, arguments, editor, false, 0, lineNumber);
+    editor->setDefaultLineNumber(lineNumber);
+    vcsExec(workingDir, arguments, editor);
     return editor;
 }