Fix reading zRAM properties from sysfs
Fix reading zRAM properties from sysfs

'/sys/block/zram<id>/num_reads' and other files are deprecated
on recent kernels. 'zram<id>/stat', 'zram<id>/mm_stat' and
'zram<id>/io_stat' is used instead.

rhinstaller/libblockdev,rhinstaller/libblockdev,rhinstaller/libblockdev