Fix failure to close file after reading whole contents

git-svn-id: https://svn.apache.org/repos/asf/jena/trunk@1612222 13f79535-47bb-0310-9956-ffa450edef68
Use Java7 try-with-resources

git-svn-id: https://svn.apache.org/repos/asf/jena/trunk@1612223 13f79535-47bb-0310-9956-ffa450edef68