[packages] strongswan: introduce /etc/ipsec.user file

enable user to add their own ip (or other) rules using
/etc/ipsec.user file on events like IPsec tunnel state change

Signed-off-by: Luka Perkov <luka@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/packages@36462 3c298f89-4303-0410-b956-a3cf2f4a3e73

net/strongswan/patches/300-include-ipsec-user-script.patch

@@ -0,0 +1,17 @@
+--- a/src/_updown/_updown.in
++++ b/src/_updown/_updown.in
+@@ -16,11 +16,9 @@
+ # or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ # for more details.
+ 
+-# CAUTION:  Installing a new version of strongSwan will install a new
+-# copy of this script, wiping out any custom changes you make.  If
+-# you need changes, make a copy of this under another name, and customize
+-# that, and use the (left/right)updown parameters in ipsec.conf to make
+-# strongSwan use yours instead of this default one.
++# Add your custom ip rules to the /etc/ipsec.user file if you need that functionality.
++
++[ -e /etc/ipsec.user ] && . /etc/ipsec.user "$1"
+ 
+ # things that this script gets (from ipsec_pluto(8) man page)
+ #