Fix, the frame exception keeper wasn't really working.
Fix, the frame exception keeper wasn't really working.

Found by running mercurial test suite, where "sys.exc_info" was
cleared during the demand import.

kayhayen/Nuitka,wfxiang08/Nuitka,tempbottle/Nuitka,tempbottle/Nuitka,tempbottle/Nuitka,kayhayen/Nuitka,tempbottle/Nuitka,wfxiang08/Nuitka,wfxiang08/Nuitka,wfxiang08/Nuitka,kayhayen/Nuitka,kayhayen/Nuitka