Signature needs to be escaped for POST methods

[jordanmhiller]

Amazon::MWS::Routines::sign_request sometimes pads the signature with "=", but it neglects to escape the signature when included in the request body.

For example, when trying to use CreateInboundShipmentPlan I received the following error from Amazon:

<?xml version="1.0"?> <ErrorResponse xmlns="https://mws.amazonservices.com/"> <Error> <Type>Sender</Type> <Code>InvalidParameterValue</Code> <Message>Invalid query string provided - AWSAccessKeyId=...&amp;Signature=...A= is not valid; the value of a query string parameter may not contain a &apos;=&apos; delimiter</Message> </Error> <RequestID>...</RequestID> </ErrorResponse>

The attached patch seems to solve the issue for me.

Routines.pm.patch.txt

[racke]

Thanks a lot, @jordanmhiller. I applied the patch through 412484c. If you want your real name in ACKNOWLEDGEMENTS, please let me know.