CVE: IDs are now 4-7 digits long
CVE: IDs are now 4-7 digits long

Reviewing the NVD feeds from
https://nvd.nist.gov/vuln/data-feeds#CVE_FEED reflects like
`CVE-2016-1000031`, `CVE-2017-18016` and `CVE-2017-1000439`.

I'm sure this xsd needs to be vetted in other places, but currently
`oscap cve validate ./nvdcve-2.0-modified.xml` fails with

```shell
File './nvdcve-2.0-modified.xml' line 65535: Element '{http://scap.nist.gov/schema/vulnerability/0.4}cve-id': [facet 'pattern'] The value 'CVE-2017-1000367' is not accepted by the pattern 'CVE-([1,2])\d{3}-\d{4}'.
File './nvdcve-2.0-modified.xml' line 65535: Element '{http://scap.nist.gov/schema/vulnerability/0.4}cve-id': 'CVE-2017-1000367' is not a valid value of the atomic type '{http://scap.nist.gov/schema/cve/0.1}cveNamePatternType'.
```

Signed-off-by: Vincent Batts <d01a4772f0cffd3f005a7d7f01c59cd104c7a5fe@hashbangbash.com>

redhatrises/openscap,OpenSCAP/openscap,jan-cerny/openscap,jan-cerny/openscap,redhatrises/openscap,OpenSCAP/openscap,mpreisler/openscap,jan-cerny/openscap,mpreisler/openscap,jan-cerny/openscap,redhatrises/openscap,mpreisler/openscap,mpreisler/openscap,OpenSCAP/openscap,jan-cerny/openscap,jan-cerny/openscap,OpenSCAP/openscap,redhatrises/openscap,redhatrises/openscap,redhatrises/openscap,OpenSCAP/openscap,mpreisler/openscap,OpenSCAP/openscap,mpreisler/openscap