package/nginx: add license hash

Signed-off-by: Samuel Martin <s.martin49@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

package/nginx/nginx.hash

@@ -1,2 +1,4 @@
 # Locally calculated after checking pgp signature
 sha256	8793bf426485a30f91021b6b945a9fd8a84d87d17b566562c3797aba8fac76fb	nginx-1.12.1.tar.gz
+# License files, locally calculated
+sha256	75820469c890db641e54078df018e497fde0542211aa704e15320316a2175780	LICENSE