network/iproute2: Bump version to 3.7.0

Updated to latest stable version and added an upstream patch to handle
a link failure

Signed-off-by: Oliver Smith <olipro@8.c.9.b.0.7.4.0.1.0.0.2.ip6.arpa>
[dgolle@allnet.de: refreshed patches]
Signed-off-by: Daniel Golle <dgolle@allnet.de>

git-svn-id: svn://svn.openwrt.org/openwrt@35250 3c298f89-4303-0410-b956-a3cf2f4a3e73