Clears the "Clear auto-opening settings" button (put it in the default state, ie, disabled), when the user  clicks in "Reset to defaults" button.
Clears the "Clear auto-opening settings" button (put it in the default state,
ie, disabled), when the user 
clicks in "Reset to defaults" button.

BUG=7334 (http://crbug.com/7334)
TEST=Download a file, enable "Always open files of this type" from download item
menu, go to Options/Under the 
Hood and then click on "Reset to defaults" button.

Contributed by tfarina (thiago.farina@gmail.com)

Review URL: http://codereview.chromium.org/174306

git-svn-id: dd90618784b6a4b323ea0c23a071cb1c9e6f2ac7@24080 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser