6relayd: try to workaround race condition at startup

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@39184 3c298f89-4303-0410-b956-a3cf2f4a3e73
Add jsonpath - a command line utility to extract values from JSON data using XPath-like expressions

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@39185 3c298f89-4303-0410-b956-a3cf2f4a3e73
Merge remotes/origin/HEAD into ravi