Add title to syslog

[knqyf263]

What did you implement:

Add title to syslog

How did you implement it:

Extract a title from CveContents of RedHat.

How can we verify it:

$ vuls report -to-syslog

$ nc -l 514
<129>2018-06-05T16:15:42+09:00 MBP vuls[52919]: scanned_at="2018-06-05 14:40:05.611697546 +0900 JST" server_name="centos6" os_family="centos" os_release="6.9" ipv4_addr="10.0.2.15,192.168.33.10" ipv6_addr="" packages="procps" cve_id="CVE-2018-1126" cwe_id="" source_link="https://nvd.nist.gov/vuln/detail/CVE-2018-1126" summary="procps-ng before version 3.3.15 is vulnerable to an incorrect integer size in proc/alloc.* leading to truncation/integer overflow issues. This flaw is related to CVE-2018-1124." title="RHSA-2018:1777: procps security update (Important)"

Todos:

You don't have to satisfy all of the following.

• 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
Is it a breaking change?: NO