Fix issue 16174 (http://projects.puppetlabs.com/issues/16174)

On RHEL 5 family systems ext4 filesystems can not be resized using resize2fs.
resize4fs from e4fsprogs (rpm -ql e2fsprogs|grep resize) is required.
Check if resizef4s exists, if so use it to resize ext4 instead of resize2fs
Merge pull request #47 from mkrakowitzer/mkrakowitzer/issue_16174_resize4fs_ext4_rhel5

Fix issue 16174 (http://projects.puppetlabs.com/issues/16174)