opensaf: remove unused service file

Upstream ships systemd service file plmcboot.service and plmcd.service now,
so we don't need this anymore.

Signed-off-by: Li Xin <lixin.fnst@cn.fujitsu.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
Signed-off-by: Joe MacDonald <joe_macdonald@mentor.com>