luci-mod-freifunk: fix lookup of community-name

luci-mod-freifunk: fix lookup of community-name

restore the lookup of the freifunk community-name stored in
uci "freifunk.community.name".
In https://github.com/openwrt/luci/commit/9780ee382e72f8a5fb69e337a3fcc51fc0914883
the value changed to the complete path of the community-profile, e.g.
"/etc/config/profile_berlin". This causes lookup problems on other
pages, like "mod-freifunk -> overview -> index" (view/freifunk/index.htm line37, line 54).
And as the option suggests it's the community-name not the community-profile path.

This is a backport of https://github.com/openwrt/luci/commit/61c7157a66b4bbce7d110cc0de8164bd2bd57798

Signed-off-by: Sven Roederer <devel-sven@geroedel.de>