Merge pull request #1880 from simonjbeaumont/cp-9229-xs64bit

[xs64bit] CP-9229: Use new path for convert-legacy-stream
CA-140684: Handle cancellation of VM migration properly

Suggested-by: Yunlei Ding <yunlei.ding@citrix.com>
Signed-off-by: Euan Harris <euan.harris@citrix.com>