OF-1781: Fix download of plugins via admin console
OF-1781: Fix download of plugins via admin console

Additionally, it no longer takes 5 seconds before the download starts. I've left a 1 second interval, for the spinner to show (which I guess is expected UX).

igniterealtime/Openfire,guusdk/Openfire,guusdk/Openfire,akrherz/Openfire,igniterealtime/Openfire,igniterealtime/Openfire,GregDThomas/Openfire,GregDThomas/Openfire,igniterealtime/Openfire,akrherz/Openfire,speedy01/Openfire,GregDThomas/Openfire,GregDThomas/Openfire,akrherz/Openfire,speedy01/Openfire,guusdk/Openfire,akrherz/Openfire,GregDThomas/Openfire,speedy01/Openfire,guusdk/Openfire,speedy01/Openfire,igniterealtime/Openfire,speedy01/Openfire,guusdk/Openfire,akrherz/Openfire