This commit modifies the ownership and access privilege of the
fault manager config file to the fm user only.
Verified the ownership and permission of /etc/fm/fm.conf after
successfully installed and unlocked a controller. No extra error
message is produced in fm-manager.log and fm-event.log. And fm
commands are functional.
Change-Id: Ief675bbe08c00bb106b7fdd6b5db46364192c69c
Closes-Bug: 1887444
Signed-off-by: Yuxing Jiang <yuxing.jiang@windriver.com>