Force creation of reiserfs on whole disk devices (#743181)

Creation of reiserfs file system fails in GParted with the this error.

    # mkreiserfs -f --label "" /dev/sdb < /dev/null
    mkreiserfs 3.6.24

    /dev/sdb is entire device, not just one partition!
    Continue  (y/n):
    # echo $?
    1

Add second force flag, -f, to the mkreiserfs command to make it work.

Bug 743181 - Add unpartitioned drive read-write support