Update ec2_plugin.py

Restore python2 compatibility

Author: yonash2

aws_xray_sdk/core/plugins/ec2_plugin.py

@@ -1,10 +1,10 @@
 import json
 import logging
 from future.standard_library import install_aliases
-from urllib.request import urlopen, Request
-
 install_aliases()
 
+from urllib.request import urlopen, Request
+
 log = logging.getLogger(__name__)
 
 SERVICE_NAME = 'ec2'