gfs_mkfs: change the way we check to see if a device is mounted
gfs_mkfs: change the way we check to see if a device is mounted

New method will attempt to open device with O_EXCL flag. If open()
responds with EBUSY, mkfs will die. This indicates that the device
is either mounted or part of a LVM volume. (BZ #426298)

asp24/resource-agents,asp24/resource-agents,stevenraspudic/resource-agents,stevenraspudic/resource-agents,stevenraspudic/resource-agents,asp24/resource-agents