compact then unique, not vice versa

Author: oreoshake

lib/secure_headers/headers/content_security_policy.rb

@@ -218,7 +218,7 @@ def combine_policies(original, additions)
         # when each hash contains a value for a given key.
         original.merge(additions) do |directive, lhs, rhs|
           if source_list?(directive)
-            (lhs.to_a + rhs.to_a).uniq.compact
+            (lhs.to_a + rhs.to_a).compact.uniq
           else
             rhs
           end