Avoid update loops by using the higher of update/download version.
Avoid update loops by using the higher of update/download version.

Fixes #1659

Ventero/greasemonkey,Martii/greasemonkey,the8472/greasemonkey,Martii/greasemonkey,HasClass0/greasemonkey,the8472/greasemonkey,Ventero/greasemonkey,HasClass0/greasemonkey