If "-" is passed in for the source, python-swiftclient will upload
the object by reading the contents of the standard input. The object
name option must be set, as well, and this cannot be used in
conjunction with other files.
This approach stores the entire contents as one object. A follow on
patch will change this behavior to upload from standard input as SLO,
unless the segment size is larger than the content size.
Change-Id: I1a8be6377de06f702e0f336a5a593408ed49be02