esx: Allow disk images in subdirectories

esx: Allow disk images in subdirectories

The esxParseVMXFileName() function parses path to a disk image
trying to replace some "known" patterns (e.g. datastore paths).
A simple filename is treated as a path relative to .vmx file. But
disk images (and thus filenames) can be in a subdirectory,
relative to the .vmx file. For instance:

  subfolder/disk.vmdk

Adapt our parser to this fact.

Resolves: https://issues.redhat.com/browse/RHEL-122751
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Martin Kletzander <mkletzan@redhat.com>