Add AWS_BUCKETNAME_UNSTRUCTURED to by-pass check

Curently the name of the bucket is cross checked with the
running environment. In rare case you can have a bucket name
that doesn't match the structure <project>-odoo-<env> in place.

README.md

@@ -81,6 +81,10 @@ Besides, the attachment location should be set to `s3` (this is
 automatically done by the `install` methods of the `cloud_platform` module).
  * `ir.config_parameter` `ir_attachment.location`: `s3`
 
+Structure of bucket name is checked against environment.
+It is possible to by-pass this behavior by using the following environment variable:
+`AWS_BUCKETNAME_UNSTRUCTURED`.
+
 
 ### Attachments in the Object Storage Swift