The fix is not really documented - you have to stop the SPAdmin (SharePoint Administration Services through Services.msc or PowerShell), run the cmdlet then start the service again. For 2013, it's:
Net Stop SPAdminV4
Net Start SPAdminV4
Remember too that for now, stsadm -o execadmsvcjobs still works (use the Management Shell so you don't have to change directories).
ALWAYS USE Run as administrator when opening the Management Shell for best results!