Make chunkedUpload match upload behavior
.upload will upload the entire file, then reject the promise
if it has warnings.
This also happened in chunkedUpload, but a warning could already
be present after uploading only 1 chunk & that rejection would
cause the entire chain of chunks to stop.
Instead, it'll now keep uploading all chunks & then reject with
the complete upload data.
Also fixed how abort is dealt with when retrying because of
network issues.
Change-Id: I8ecef2271359a9505c8c5fa22883b0df55e9e914