package/busybox: update configuration file
Commit
44a563dbc04ec8e51c5262201cd1745617055b78 bumps busybox to version
1.26.0, but does not update the configuration file. There is at least
one issue using the old configuration with the newer busybox:
* IFUPDOWN is split into IFUP and IFDOWN in version 1.26.0
Update the configuration file by loading the busybox.config file and
saving it back.
Signed-off-by: Jörg Krause <joerg.krause@embedded.rocks>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>