Fixes check for valid row when restoring selection. The problem was that if the saved selection was in a closed section, numberOfSectionsInTableView would be zero which would cause the check to continue, wiping out the saved selection and selecting the first item instead. Fixed #1574

git-svn-id: http://ios.svn.wordpress.org/trunk@4126 7d847f7c-ffe1-4a24-85be-b788d016d96a