retry file download from instfs on open timeout
retry file download from instfs on open timeout

since we're already retrying on read as well

refs #LA-1073

Change-Id: Ieb1dd4adbe7a98f9d144bce05dec7600c6833a4e
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/238431
Tested-by: Service Cloud Jenkins <9144042a601061f88f1e1d7a1753ea3e2972119d@instructure.com>
Reviewed-by: Jeremy Stanley <b3f594e10a9edcf5413cf1190121d45078c62290@instructure.com>
QA-Review: Jeremy Stanley <b3f594e10a9edcf5413cf1190121d45078c62290@instructure.com>
Product-Review: Jeremy Stanley <b3f594e10a9edcf5413cf1190121d45078c62290@instructure.com>

sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms