mke2fs: clean up kernel version tests

Refactor the running kernel version checks to hide the details of
version code checking, etc.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
1 file changed