patches/packages: luajit: install lubluajit and add hpp to InstallDev
After:
Discoved because of knot-resolver:
Package knot-resolver is missing dependencies for the following libraries:
libluajit-5.1.so.2
Shortly, there will be send pull request with cherry-picks to packages repository for openwrt-18.06. Ref: https://github.com/openwrt/packages/pull/6722