datastore/mkfs: FSTYPE could be empty string (one 6.0+)
datastore/mkfs: FSTYPE could be empty string (one 6.0+)

Signed-off-by: Anton Todorov <e150cc19eb43409ef4fcf4ffefb16532fb2bc38e@storpool.com>

OpenNebula/addon-storpool,OpenNebula/addon-storpool,OpenNebula/addon-storpool