support/scripts/pkg-stats: verified CPE has a known id but not version

support/scripts/pkg-stats: verified CPE has a known id but not version

Currently a verified CPE reports the following if versions are not found
 cpe:2.3:a:qemu:qemu:5.2.0:*:*:*:*:*:*:*
 CPE identifier unknown in CPE database (Search)

This patch clarifies the report to state the 'version' is unknown instead
of the 'identifier'.

Cc: Yann E. MORIN <yann.morin.1998@free.fr>
Signed-off-by: Matthew Weber <matthew.weber@collins.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>