* slash direction

The /lib/gluon/upgrade/500-ssid-changer script is called when the device is
initialized, reconfigured or upgraded. It will set the configuration to the
site content and prepare everything for the actual gluon_ssid_changer
script.

But it will check whether the ssid-changer.settings.enabled entry exists.
If it does, then it will just ignore the values from the site and skip the
initialization. But the problem here is that the package already provides
this entry in his standard initialization. The section will therefore never
get initialized and thus the package is disabled on all installations.

Instead just copy the content of ssid-changer.settings.enabled when it
exists and otherwise use the data from the site. And the rest of the
configuration must always be copied from the site.

All places in the gluon_ssid_changer source code use the type "settings"
for the main config section of the package. But the upgrade script switches
this to "main" for no obvious reason.

The gluon.site module request that the structure elements are called to get
the actual content of the string. The simple-uci will not do that and
instead cause an exception because the caller didn't provide a string.

closes #19

Siehe https://github.com/freifunk-gluon/gluon/commit/7ccdacd294e5fcb6718f806543bb2620c02c9ddb