Clean up broken JSON samples

Closes-Bug: #1283713

Change-Id: Ic89203e7b955b07482916cb10870e4b3a47b252f
author: diane fleming
Update volume create

Update request and responses
Add parameter descriptions

Partial-Bug: #1224332

Change-Id: If14e3d3267eb7ef6552f79e371bc311d53b59dfe
author: diane fleming
Add description of changes-since to Image Service v1 API document

'changes-since' was prepared as a option of Image Service v1 API,
but there is no description on API document.
So I added the description.

Change-Id: I146334709ac038574ee381c15725e59d2c4c0e46
Merge "Clean up broken JSON samples"
Merge "Update volume create"
Merge "Add description of changes-since to Image Service v1 API document"