utils/new_module: Fix github_user test

new_module was always failing with "github_user is not valid". The wrong
variable was checked: $githubuser instead of $github_user.

utils/new_module

@@ -78,7 +78,7 @@ if [ -z "$name" ] || [ -z "$author" ] || [ -z "$email" ] || [ -z "$github_user"
     [ -z "$name" ] && echo "ERROR: name is not valid"
     [ -z "$author" ] && echo "ERROR: author is not valid"
     [ -z "$email" ] && echo "ERROR: email is not valid"
-    [ -z "$githubuser" ] && echo "ERROR: github_user is not valid"
+    [ -z "$github_user" ] && echo "ERROR: github_user is not valid"
     echo
     usage;
     exit 1;