Distinguish between a BlockDev's current and recorded size
Distinguish between a BlockDev's current and recorded size

These are both valuable numbers to know, and they may be different if
Stratis was set up and a device's size was different from that recorded.

It is also possible to compare the sizes to find out if they are different
by using these two distinct methods.

Signed-off-by: mulhern <7b51bcf507bcd7afb72bf8663752c0ddbeb517f6@redhat.com>

stratis-storage/stratisd,trgill/stratisd,stratis-storage/stratisd,stratis-storage/stratisd,trgill/stratisd,mulkieran/stratisd,mulkieran/stratisd