Java: fix syntax error in path-injection example fix

Author: smowton

java/ql/src/Security/CWE/CWE-022/TaintedPath.java

@@ -16,9 +16,9 @@ public void sendUserFileFixed(Socket sock, String user) {
 	// ...
 
 	// GOOD: remove all dots and directory delimiters from the filename before using
-	String filename = filenameReader.readLine().replaceAll("\.", "").replaceAll("/", "");
+	String filename = filenameReader.readLine().replaceAll("\\.", "").replaceAll("/", "");
 	BufferedReader fileReader = new BufferedReader(
 			new FileReader("/home/" + user + "/" + filename));
 
 	// ...
-}
+}