[FIX] upgrade: Check the prefs in the database for feature_search setting and set both search prefs if it's 'y' or empty (which was the default prior to r45122) to avoid settings being switched around (thanks Geoff)

git-svn-id: file:///var/local/code.tiki.org/tikisvn/branches/11.x@46392 b456876b-0849-0410-b77d-98878d47e9d5