The root cause is that sftp path in sshd_config is not right.
It should be changed from /usr/libexec/sftp-server
to /usr/libexec/openssh/sftp-server
Verified in my deployment environment
sftp can connect to controller.
Closes-Bug: 1808054
Change-Id: Ia8d00abc1f18bc3b46faadd87f8ed153a446b7b0
Signed-off-by: zhipengl <zhipengs.liu@intel.com>