strongswan: add missing config files for plugins

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/packages@40524 3c298f89-4303-0410-b956-a3cf2f4a3e73
Merge branch 'master' into smm
[tgt] fix conffiles: remove leading tab