cve-check: do not skip cve status description after :

cve-check: do not skip cve status description after :

Correct maxsplit parameter from 5 to 4 to not drop text if
description contains ":".

Example:
>>> "detail: cpe:vendor:product:description:cont".split(':', 5)
['detail', ' cpe', 'vendor', 'product', 'description', 'xxx']
>>> "detail: cpe:vendor:product:description:cont".split(':', 4)
['detail', ' cpe', 'vendor', 'product', 'description:xxx']

Signed-off-by: Peter Marko <peter.marko@siemens.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>