Remove double equals.

== is a bash specific alias for = , and
should not be used in #!/bin/sh scripts. Not in #!/usr/bin/haserl scripts
either, where the shell defaults to /bin/sh.

Signed-off-by: Robert Langhammer <rlanghammer@web.de>
Reviewed-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>
Reviewed-by: Tim Niemeyer <tim@tn-x.org>
- rebased
Signed-off-by: Tim Niemeyer <tim@tn-x.org>