cherry pick swagger-api#8049

Author: Carlo Carraro

modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/ErlangServerCodegen.java

@@ -110,6 +110,15 @@ public ErlangServerCodegen() {
          */
         additionalProperties.put("apiVersion", apiVersion);
         additionalProperties.put("apiPath", apiPath);
+    }
+
+    @Override
+    public void processOpts() {
+        super.processOpts();
+
+        if (additionalProperties.containsKey(CodegenConstants.PACKAGE_NAME)) {
+            setPackageName((String) additionalProperties.get(CodegenConstants.PACKAGE_NAME));
+        }
         /**
          * Supporting Files.  You can write single files for the generator with the
          * entire object tree available.  If the input file has a suffix of `.mustache