fix(cpescan): match if affected version is NA

[kotakanbe]

What did you implement:

vulsio/go-cve-dictionary#283

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

after

$ grep -C1 forti config.toml
  [servers.forti]
    cpeNames = ["cpe:/h:fortinet:fortigate-100d:v6.2.9"]
    type = "pseudo"
$ ./vuls scan forti
$./vuls report
forti (pseudo)
==============
Total: 2 (Critical:0 High:0 Medium:2 Low:0 ?:0)
0/0 Fixed, 1 poc, 0 exploits, cisa: 0, uscert: 0, jpcert: 0 alerts
0 installed

+---------------+------+--------+-----+-----------+---------+----------+
|    CVE-ID     | CVSS | ATTACK | POC |   ALERT   |  FIXED  | PACKAGES |
+---------------+------+--------+-----+-----------+---------+----------+
| CVE-2012-4948 |  5.3 |  AV:A  |     |           |         |          |
+---------------+------+--------+-----+-----------+---------+----------+
| CVE-2013-1414 |  5.1 |  AV:N  | POC |           |         |          |
+---------------+------+--------+-----+-----------+---------+----------+

before

$ ./vuls.new report --refresh-cve
forti (pseudo)
==============
Total: 0 (Critical:0 High:0 Medium:0 Low:0 ?:0)
0/0 Fixed, 0 poc, 0 exploits, cisa: 0, uscert: 0, jpcert: 0 alerts
0 installed

https://nvd.nist.gov/vuln/detail/CVE-2012-4948

Checklist:

• Write tests
• Write documentation
• Check that there aren't other open pull requests for the same issue/feature
• Format your source code by make fmt
• Pass the test by make test
• Provide verification config / commands
• Enable "Allow edits from maintainers" for this PR
• Update the messages below

Is this ready for review?: YES