LU-12226 debian: fix debhelper level requirement

LU-12226 debian: fix debhelper level requirement

Requiring debhelper-compat = 12 will break the build on
Ubuntu 18.04 LTS, it only has debhelper 11.

Revert to Standards-Version: 4.4.1 for Ubuntu 18.04 build.

Fixes: a77d7a07b885 ("debian: switch to using build dependency on debhelper-compat")
Fixes: c2b1ec5fbc99 ("Update release notes, etc., for the 1.45.5 release")
Change-Id: I40838a4de5ee7a841ba970d4f7531f8fe9dc5ff4
Signed-off-by: Li Dongyang <dongyangli@ddn.com>
Reviewed-by: Minh Diep <mdiep@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>