Fixed FindBugs reported bug in initialDelay calculation - actually this would...

Fixed FindBugs reported bug in initialDelay calculation - actually this would probably only go wrong once in 10000 years or so, but better be safe ;)

core/src/main/java/hudson/model/AperiodicWork.java

@@ -74,7 +74,11 @@ public abstract class AperiodicWork extends SafeTimerTask implements ExtensionPo
      * By default it chooses the value randomly between 0 and {@link #getRecurrencePeriod()}
      */
     public long getInitialDelay() {
-        return Math.abs(RANDOM.nextLong())%getRecurrencePeriod();
+        long l = RANDOM.nextLong();
+        // Math.abs(Long.MIN_VALUE)==Long.MIN_VALUE!
+        if (l==Long.MIN_VALUE)
+            l++;
+        return Math.abs(l)%getRecurrencePeriod();
     }
 
     @Override

core/src/main/java/hudson/model/PeriodicWork.java

@@ -75,7 +75,11 @@ public abstract class PeriodicWork extends SafeTimerTask implements ExtensionPoi
      * By default it chooses the value randomly between 0 and {@link #getRecurrencePeriod()}
      */
     public long getInitialDelay() {
-        return Math.abs(RANDOM.nextLong())%getRecurrencePeriod();
+        long l = RANDOM.nextLong();
+        // Math.abs(Long.MIN_VALUE)==Long.MIN_VALUE!
+        if (l==Long.MIN_VALUE)
+            l++;
+        return Math.abs(l)%getRecurrencePeriod();
     }
 
     /**