Revert "SPARK-3608 Break if the instance tag naming succeeds"

This reverts commit 78d4220.

Author: mengxr

ec2/spark_ec2.py

@@ -503,7 +503,6 @@ def tag_instance(instance, name):
     for i in range(0, 5):
         try:
             instance.add_tag(key='Name', value=name)
-            break
         except:
             print "Failed attempt %i of 5 to tag %s" % ((i + 1), name)
             if i == 5: