Fix debian OS determination

[jturel]

Running Transaction                             
  Installing : katello-ca-consumer-centos7-dev2.strangeways.example.com-1.0-1.noarch                                                                                                           1/1 
sed: can't read /etc/os-release: No such file or directory                                       
warning: %post(katello-ca-consumer-centos7-dev2.strangeways.example.com-1.0-1.noarch) scriptlet failed, exit status 2                                                                              
Non-fatal POSTIN scriptlet failure in rpm package katello-ca-consumer-centos7-dev2.strangeways.example.com-1.0-1.noarch                                                                              Verifying  : katello-ca-consumer-centos7-dev2.strangeways.example.com-1.0-1.noarch                                                                                                           1/1 

Installed:                                      
  katello-ca-consumer-centos7-dev2.strangeways.example.com.noarch 0:1.0-1 

Hmm, what happened?

[root@rhel6 vagrant]# katello-rhsm-consumer
sed: can't read /etc/os-release: No such file or directory

Ah! We don't have os-release in EL6.. I think I've fixed it. I also corrected the regex by adding a '^' in front of 'ID' since it was matching too much.

[jturel]

@mdellweg you might wanna confirm my regex change :)

[mdellweg]

Looks good. If you like, you can also add $ to the end of the regex to be really sure.

[ekohl]

Looks good. If you like, you can also add $ to the end of the regex to be really sure.

Isn't that a bit redundant with a greedy regex?

[mdellweg]

Sure. I tend to forget, which regex implementations are greedy, and this redundancy might not hurt. But i'm fine with either ways.

[sean797]

Thanks @jturel 👍

[ekohl]

Should this be merged then @mdellweg?

[mdellweg]

@ekohl I'm fine.

Sorry for breaking CentOS6 in the first place.