sysctlfile: add newline for value invocations

/etc/init/procps does "cat /etc/sysctl.d/*.conf /etc/sysctl.conf | sysctl
-e -p", so not having a newline means at best means settings being
ignored, at worst means having random keys being set as values of other
keys...

Change-Id: I8dcc5779b06c188f8cc6c16c3011f252c1736180