Add a comment to make it clear that we are doubling the size of meta
Add a comment to make it clear that we are doubling the size of meta

When the meta is expanded we pass in the current size as the requested
extension size.  Added a variable/comment to make it more clear.

Signed-off-by: Todd Gill <7afbb5ba98932b8ffb9cc9e6675c4792db142529@redhat.com>

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