Description of problem:
 When detecting the disk layout for a system with Advanced Format (AF) disks, the size of the disk is incorrect. 

Version-Release number of selected component (if applicable):
 rear-1.17.2-6.el7

How reproducible:
 Easily, with the correct disks

Steps to Reproduce:
1. Install and configure rear for basic use including most/all local storage
2. Verify that one or more disks report a value greater than 512 for /sys/block/<disk>/queue/logical_block_size
3. Create a rescue image
4. Verify in the resulting disklayout.conf that the size of the disk is correct

Actual results:
 The disk will be reported as significantly larger than it actually is

Expected results:
 The disk will be reported as the correct size

Additional info:
 This is due to the use of the "logical_block_size" interface exposed by the kernel via the sysfs filesystem. The value found is used as the multiplier for the "size" interface. However, the "size" interface is always in 512 byte blocks. Regardless of the "logical_block_size".