lua-resty-http: correct license file path

LICENSE file is present in subdirectory.

Fixes:
  http://autobuild.buildroot.net/results/d33/d33a322b4d2618b55849b5637082100702a91eea

Signed-off-by: Rahul Bedarkar <rahulbedarkar89@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/lua-resty-http/lua-resty-http.mk

@@ -7,6 +7,6 @@
 LUA_RESTY_HTTP_VERSION = 0.10-0
 LUA_RESTY_HTTP_SUBDIR = lua-resty-http
 LUA_RESTY_HTTP_LICENSE = BSD-2-Clause
-LUA_RESTY_HTTP_LICENSE_FILES = LICENSE
+LUA_RESTY_HTTP_LICENSE_FILES = $(LUA_RESTY_HTTP_SUBDIR)/LICENSE
 
 $(eval $(luarocks-package))