"[[" is a bash extension for test. As the ash-implementation is not
fully compatible we drop its usage.
This follows up 3519bf4976
As a result, we also need to move the and/or out of the test brackets.
Signed-off-by: Sven Roederer <devel-sven@geroedel.de>
[squash from two patches, adjust commit message]
Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>
7e67d14486