xenserver_guest_info: use fallback chain for VDI format detection (#12215)
* xenserver_guest_info: use fallback chain for VDI format detection
* changelog: add PR URL to
changelog fragment
* test: set mismatched vdi_type in vm-3 fixture to test fallback chain precedence
Set vdi_type to "vhd" while image-format remains "qcow2" so the unit
test verifies that image-format takes precedence in the fallback chain.
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(cherry picked from commit 4d72ec3299)
Co-authored-by: Shreyash <shrbhosa@redhat.com>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
cdab3ee401