Merge pull request #102 from ccliangbo/waitNewUrl

combine two try-catch block into one, make it cleaner.

webmagic-core/src/main/java/us/codecraft/webmagic/Spider.java

@@ -489,17 +489,17 @@ public class Spider implements Runnable, Task {
     }
 
     private void waitNewUrl() {
-        try {
         newUrlLock.lock();
+        try {
             //double check
             if (threadAlive.get() == 0 && exitWhenComplete) {
                 return;
             }
-            try {
             newUrlCondition.await();
         } catch (InterruptedException e) {
+            logger.warn("waitNewUrl - interrupted, error {}", e);
         }
-        } finally {
+        finally {
             newUrlLock.unlock();
         }
     }