Description of problem:
Default value of $releasever is set to "7.5" instead of  "7$Variant", due to this yum repolist is failing with HTTPS Error 403 - Forbidden

Version-Release number of selected component (if applicable):
#  rpm -q redhat-release-server
redhat-release-server-7.5-0.12.el7.x86_64


How reproducible:
always

Steps to Reproduce:
1.Install RHEL75 Develphase exit build --> server variant
2.Register and subscribe system from stage
3.execute yum repolist

[root@dhcp35-157 ~]# subscription-manager register --auto-attach
Registering to: subscription.rhsm.stage.redhat.com:443/subscription
Username: user
Password: 
The system has been registered with ID: 5178ce49-d909-44fc-8015-0070453589d1
The registered system name is: dhcp35-157.lab.eng.blr.redhat.com
Installed Product Current Status:
Product Name: Red Hat Enterprise Linux Server
Status:       Subscribed

[root@dhcp35-157 ~]# yum repolist
Loaded plugins: langpacks, product-id, search-disabled-repos, subscription-manager
https://cdn.redhat.com/content/dist/rhel/server/7/7.5/x86_64/os/repodata/repomd.xml: [Errno 14] HTTPS Error 403 - Forbidden
Trying other mirror.
To address this issue please refer to the below knowledge base article

https://access.redhat.com/solutions/69319

If above article doesn't help to resolve this issue please open a ticket with Red Hat Support.

https://cdn.redhat.com/content/dist/rhel/server/7/7.5/x86_64/os/repodata/repomd.xml: [Errno 14] HTTPS Error 403 - Forbidden
Trying other mirror.
repo id     repo name                                 status
rhel-7-server-rpms/7.5/x86_64 Red Hat Enterprise Linux 7 Server (RPMs)  0
repolist: 0
^^ NOTICE 7.5 HAS BEEN USED INSTEAD OF 7SERVER, HENCE NO CONTENT AVAILABLE


Actual results:
Observed $releaserver is using the "7.5" instead of "7Server"

Expected results:
$releaserver should be using "7$Variant"

Additional info:
on a RHEL74 machine 
-----------------------
# python -c 'import yum, pprint; yb = yum.YumBase(); pprint.pprint(yb.conf.yumvar, width=1)'
Loaded plugins: product-id
{'arch': 'ia32e',
 'basearch': 'x86_64',
 'releasever': '7Server',
 'uuid': 'c83b7a2b-3414-4179-b023-1401cde881a6'}
[root@dell-pem600-01 ~]# 


ON RHEL75 
==========

# python -c 'import yum, pprint; yb = yum.YumBase(); pprint.pprint(yb.conf.yumvar, width=1)'
Loaded plugins: langpacks, product-id, subscription-manager
{'arch': 'ia32e',
 'basearch': 'x86_64',
 'releasever': '7.5',
 'uuid': 'c355538f-c3e7-4f4b-ae35-a31b507882a5'}
[root@dhcp35-157 ~]#