[bug] /usr/sbin/katello-certs-check does not handle case sensitivity (upper/lower) of the CN and SAN and errors out

Description of problem:
/usr/sbin/katello-certs-check will error when the certificate has the same FQDN in CN and SAN, but one is uppercase and another is in lowercase.

How reproducible:
Always 

Steps to Reproduce:

1. create custom certificate with lower case CN name and SAN with uppercase

2. Run 'satellite-installer' and it will fail

Actual behavior:
Error shows as below:
~~~
Checking if any Subject Alt Name on certificate matches the Subject CN
[FAIL]

The /root/satellite_cert/satellite_cert.pem does not have a Subject Alt Name matching the Subject CN
Checking Key Usage extension on certificate for Key Encipherment
~~~

Expected behavior:
It should not be case sensitive

Business Impact / Additional info: