LU-14895 client: allow case-insensitive checksum types

LU-14895 client: allow case-insensitive checksum types

The current t10ip4K and t10crc4K checksum types use an upper-case 'K'
in the name, unlike the other checksum types which are all lower-case.
This is distinction is difficult to see in some fonts, and can cause
usage errors.  Accept upper-case variants of the checksum type names.

Lustre-change: https://review.whamcloud.com/44530
Lustre-commit: TBD (from 48a8218fdd0d0ed876fb39d29542fd1751c2e341)

Test-Parameters: trivial
Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Change-Id: I97673ffa98cf8e5fc601ac7df5aaafb24b3ebbe5
Reviewed-by: Li Dongyang <dongyangli@ddn.com>
Reviewed-by: Alex Zhuravlev <bzzz@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/44940
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>