add a number of null check to return methods.

This allows calling these methods on error cleanup paths without having
to surround them with if checks all the time.

src/main/java/redis/clients/util/Pool.java

@@ -54,11 +54,15 @@ public abstract class Pool<T> {
     }
 
     public void returnBrokenResource(final T resource) {
-	returnBrokenResourceObject(resource);
+	if (resource != null) {
+	    returnBrokenResourceObject(resource);
+	}
     }
 
     public void returnResource(final T resource) {
-	returnResourceObject(resource);
+	if (resource != null) {
+	    returnResourceObject(resource);
+	}
     }
 
     public void destroy() {
@@ -81,4 +85,4 @@ public abstract class Pool<T> {
 	    throw new JedisException("Could not destroy the pool", e);
 	}
     }
-}
+}