logic: associating blockdevices with storage

[AmitKumarDas]

This is the current logic that is followed by default openebs operators to create CStor Pools.

	err = blockdevice.
		BuilderForAPIObject(bdObj).
		BlockDevice.
		ValidateBlockDevice(
			blockdevice.CheckIfBDIsActive(),
			blockdevice.CheckIfBDIsNonFsType(),
			blockdevice.CheckIfBDBelongsToNode(poolValidator.nodeName))

However, cstorpoolauto does not make check for presence of file on the device. This issue should have the details if filesystem should be considered at all to select a device.