upload does not fall back to Agave API on PermissionError

[tcmitchell]

If a user does not have permission to write a file via the direct API, and does have permission to write a file via the Agave API, upload will not work.

When the PermissionError is raised by the direct API, upload aborts. Instead, this error should be detected and wrapped in a DirectOperationFailed exception so that the Agave API can be tried.