Merge pull request #5111 from cgundogan/pr/oonf_api/new_repo_url

pkg/oonf_api: use new repo url

pkg/oonf_api/Makefile

 PKG_NAME=oonf_api
-PKG_URL=http://olsr.org/git/oonf.git
+PKG_URL=https://github.com/OLSR/OONF.git
 PKG_VERSION=v0.3.0
 PKG_DIR=$(CURDIR)/$(PKG_NAME)