Allow to specify segment container

Fix bug 1110924

Add segment container option as part of 'swift upload -S'. If this
option is omitted, the segments will go to <container>_segments.

Example:
$ swift upload c1 obj1 -S 1 -C user_segments

Please check swift upload --help for more details

Change-Id: Ib71aae322485d8d3ac89916d37ebcac053f49e3b
Merge "Allow to specify segment container"