Fix: "Reboot Required" detection process in scan/redhat.go

[mai346]

What did you implement:

Closes #533

How did you implement it:

If "kernel" can not be found, we set the return value of "rebootRequired ()" to false.
ERROR was changed to WARN.

How can we verify it:

Scan the environment (container or paravirtualized environment) where the "kernel" is not installed.

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?: NO
Is it a breaking change?: NO

[kotakanbe]

Memo:

CentOS7 on Docker/Mac

[root@dfde34229d36 /]# rpm -q --last kernel
package                                       kernel is not installed

[kotakanbe]

@mai346
What is the output of rpm -q --last kernel on your paravirtualized environment?

If its output is also kernel is not installed, it may be better to add if statement and compare it with kernel is not installed, and return false.

[mai346]

@kotakanbe
The definition of paravirtualization may be ambiguous, but the same result is obtained except that the message becomes Japanese. (LANG=ja_JP.UTF-8)

• CentOS 7.4 on Windows Subsystem for Linux / Windows 10 RS3
• CentOS 6.0 on coLinux 0.7.4 / WinXP

I think that it is better not to judge by stdout.

[kotakanbe]

Many Thanks!

I tested on centos7/docker-mac.