CA-125060: add bash completion for '{base,into}-vdi-uuid' params of 'xe vdi-copy'

Signed-off-by: Rob Hoes <rob.hoes@citrix.com>
Merge pull request #1600 from robhoes/vdi

CA-125060: add bash completion for '{base,into}-vdi-uuid' params of 'xe ...
CP-6172: Don't specify VBD backend-kind by default

Rather than defaulting this value (meaning we have to keep parity with
xenopsd), leave the default to be determined by xenopsd itself by not
specifying a backend-kind.

Signed-off-by: Si Beaumont <simon.beaumont@citrix.com>
Merge pull request #1603 from simonjbeaumont/cp-6172-xapi-part

CP-6172: Don't specify VBD backend-kind by default