LU-13347 kernel: RHEL 7.8 server support

LU-13347 kernel: RHEL 7.8 server support

This patch makes changes to support new RHEL 7.8 release
for Lustre server (kernel 3.10.0-1127.el7).

Test-Parameters: trivial clientdistro=el7.8 serverdistro=el7.8

Change-Id: I4817fd2f9512111aa7d26109454104945fd2778f
Signed-off-by: Jian Yu <yujian@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/38144
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Minh Diep <mdiep@whamcloud.com>
Reviewed-by: Yang Sheng <ys@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>