Make run field volatile because it is shared between threads

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/io/trunk@1002908 13f79535-47bb-0310-9956-ffa450edef68

Author: sebbASF

src/java/org/apache/commons/io/input/Tailer.java

@@ -61,7 +61,7 @@ public class Tailer implements Runnable {
     /**
      * The tailer will run as long as this value is true.
      */
-    private boolean run = true;
+    private volatile boolean run = true;
 
     /**
      * The object which will be responsible for actually reading the file.