Bug fix

git-svn-id: http://primefaces.googlecode.com/svn/primefaces/trunk@10238 5a70e874-a5cb-11dd-8af2-493fb0bb9f7c
Add empty string check

git-svn-id: http://primefaces.googlecode.com/svn/primefaces/trunk@10239 5a70e874-a5cb-11dd-8af2-493fb0bb9f7c