Added support for synchronous requests.
This is needed to address the fact that QtWebKit from v2.2 forwards no longer creates its own event loop to handle such requests. Instead it expects QNAM, or any reimplementation, to deal with it on its behalf. Credit goes to Pierre Rossi for discovering this issue. BUG: 231932 FIXED-IN: 4.7.0 REVIEW: 101876 (cherry picked from commit c3e213d9)