Even if SYSTEMD_AUTO_ENABLE is set to "enable", the service is never
activated by systemd. The cause is the postinst function in the recipe:
 pkg_postinst_${PN} () {
         if [ -n "$D" ]; then
                 exit 0
         fi
         if [ -e /etc/init.d/populate-volatile.sh ]; then
                 /etc/init.d/populate-volatile.sh update
         fi
 }
This generates with activated systemd the following postinst script:
	set -e
	        if [ -n "$D" ]; then
	                exit 0
	        fi
	        if [ -e /etc/init.d/populate-volatile.sh ]; then
	                /etc/init.d/populate-volatile.sh update
	        fi
	OPTS=""
	if [ -n "$D" ]; then
	    OPTS="--root=$D"
	fi
	if type systemctl >/dev/null 2>/dev/null; then
		if [ -z "$D" ]; then
			systemctl daemon-reload
		fi
		systemctl $OPTS enable sysstat.service
		if [ -z "$D" -a "enable" = "enable" ]; then
			systemctl --no-block restart sysstat.service
		fi
	fi
Due to the exit statement, systemctl is never called and the service is
never enabled in rootfs.
Invert the logic for the check to let run the rest of postinst script.
Signed-off-by: Stefano Babic <sbabic@denx.de>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
 }
 
 pkg_postinst_${PN} () {
-        if [ -n "$D" ]; then
-                exit 0
-        fi
-        if [ -e /etc/init.d/populate-volatile.sh ]; then
-                /etc/init.d/populate-volatile.sh update
-        fi
+       if [  ! -n "$D" ]; then
+               if [ -e /etc/init.d/populate-volatile.sh ]; then
+                       /etc/init.d/populate-volatile.sh update
+               fi
+       fi
 }
 
 FILES_${PN} += "${libdir}/sa ${systemd_system_unitdir}"