Follow up for 8ed7c92e798a4bb41efd007e42957a852df0160a

Raise http exceptions in case of BadRequest

Follow `requests` api in error handling.
Merge pull request #12597 from ticosax/salt-cloud-urllib2-requests-errors

Follow up for 8ed7c92e798a4bb41efd007e42957a852df0160a