Re-notify the config observer when changing the installed script.
Re-notify the config observer when changing the installed script.

Fixes #1535

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