Add total_size to ListVmDisksResponse

BUG=chromium:822499
TEST=Builds

Change-Id: I90fd8272de1f811bf809dfd2ad4463db599da6b7
Reviewed-on: https://chromium-review.googlesource.com/1080156
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Commit-Ready: Jeffrey Kardatzke <jkardatzke@google.com>
Tested-by: Jeffrey Kardatzke <jkardatzke@google.com>
Reviewed-by: Chirantan Ekbote <chirantan@chromium.org>
1 file changed