Change s3 module to use shared ec2 authorization module snippet

library/cloud/s3

@@ -272,9 +272,9 @@ def main():
     mode = module.params.get('mode')
     expiry = int(module.params['expiry'])
     s3_url = module.params.get('s3_url')
-    aws_secret_key = module.params.get('aws_secret_key')
-    aws_access_key = module.params.get('aws_access_key')
     overwrite = module.params.get('overwrite')
+
+    ec2_url, aws_access_key, aws_secret_key, region = get_ec2_creds(module)
     
     if module.params.get('object'):
         obj = os.path.expanduser(module.params['object'])
@@ -283,18 +283,6 @@ def main():
     if not s3_url and 'S3_URL' in os.environ:
         s3_url = os.environ['S3_URL']
 
-    if not aws_secret_key:
-        if  'AWS_SECRET_KEY' in os.environ:
-            aws_secret_key = os.environ['AWS_SECRET_KEY']
-        elif 'EC2_SECRET_KEY' in os.environ:
-            aws_secret_key = os.environ['EC2_SECRET_KEY']
-
-    if not aws_access_key:
-        if 'AWS_ACCESS_KEY' in os.environ:
-            aws_access_key = os.environ['AWS_ACCESS_KEY']
-        elif 'EC2_ACCESS_KEY' in os.environ:
-            aws_access_key = os.environ['EC2_ACCESS_KEY']
-
     # If we have an S3_URL env var set, this is likely to be Walrus, so change connection method
     if is_walrus(s3_url):
         try:
@@ -463,8 +451,8 @@ def main():
 
     module.exit_json(failed=False)
 
-
-# this is magic, see lib/ansible/module_common.py
-#<<INCLUDE_ANSIBLE_MODULE_COMMON>>
+# import module snippets
+from ansible.module_utils.basic import *
+from ansible.module_utils.ec2 import *
 
 main()