vnstat: avoid adding the same interface over and over when running uci-defaults against already existing config

git-svn-id: svn://svn.openwrt.org/openwrt/packages@36716 3c298f89-4303-0410-b956-a3cf2f4a3e73
Merge remote-tracking branch 'upstream/master'
[quagga] Update to v0.99.22

git-svn-id: svn://svn.openwrt.org/openwrt/packages@36717 3c298f89-4303-0410-b956-a3cf2f4a3e73
[packages] babeld: new upstream release 1.4.1

git-svn-id: svn://svn.openwrt.org/openwrt/packages@36728 3c298f89-4303-0410-b956-a3cf2f4a3e73
Merge remote-tracking branch 'upstream/master'