Fix FileInputStream model

Author: egregius313

java/ql/lib/ext/java.io.model.yml

@@ -132,4 +132,4 @@ extensions:
       pack: codeql/java-all
       extensible: sourceModel
     data:
-      - ["java.io", "FileInputStream", True, "FileInputStream", "", "", "ReturnValue", "file", "manual"]
+      - ["java.io", "FileInputStream", True, "FileInputStream", "", "", "Argument[this]", "file", "manual"]