HADOOP-15379. Make IrqHandler.bind() public. Contributed by Ajay Kumar

(cherry picked from commit ec1e8c1a8c)

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/service/launcher/IrqHandler.java

@@ -86,7 +86,7 @@ public final class IrqHandler implements SignalHandler {
    * Bind to the interrupt handler.
    * @throws IllegalArgumentException if the exception could not be set
    */
-  void bind() {
+  public void bind() {
     Preconditions.checkState(signal == null, "Handler already bound");
     try {
       signal = new Signal(name);