Remove some obsolete FIST points (resubmit)

Resubmit of 91e03ab1a0718c6caf5a18bfc25c99d374dcc337, which
was reverted.

Signed-off-by: Rob Hoes <rob.hoes@citrix.com>
CP-4500: Added handler skeleton for /export_raw_vdi

Signed-off-by: Si Beaumont <simon.beaumont@citrix.com>
CP-4500: Move helper functions to shared import/export code

Moved some functions in import_raw_vdi.ml into shared module importexport.ml
ready for implementing export_raw_vdi:

    * return_302_redirect
    * vdi_of_req

Signed-off-by: Si Beaumont <simon.beaumont@citrix.com>
CP-4500: Implemented export_raw_vdi.

This can be called via HTTP at <host>/export_raw_vdi?vdi=<vdi-uuid> using, for
example, curl and is the counterpart to import_raw_vdi.

Signed-off-by: Si Beaumont <simon.beaumont@citrix.com>
CP-4350: Add unit test for apply_edition_with_rollback

Signed-off-by: John Else <john.else@citrix.com>
CP-4500: Fixed typo post review

Signed-off-by: Si Beaumont <simon.beaumont@citrix.com>
Merge pull request #1151 from simonjbeaumont/CP-4500

CP-4500: Implement export_raw_vdi handler
Merge pull request #1155 from johnelse/test-pool-apply-edition

CP-4350: Add unit test for apply_edition_with_rollback

Woohoo unit tests!
Merge pull request #1127 from robhoes/fist

Remove some obsolete FIST points (resubmit)