Description of problem:
when using rhnreg_ks with "--proxy=" option, it fails 

Version-Release number of selected component (if applicable):


How reproducible:


Steps to Reproduce:
1.
[root@vimappss-vrhel7 ~]# rhnreg_ks --serverUrl=https://linux-mgmt.itoper.local/XMLRPC --sslCACert=/usr/share/rhn/RHN-ORG-TRUSTED-SSL-CERT --activationkey=2-bfe6618f6b7348f605b8ed80116bbc74,2-af481ade4e5e8817104a49bae1d0bf9a --proxy=http://10.174.96.50:8080 --profilename=vimappss-vrhel7.it.bwns.ch
An error has occurred:
<class 'AttributeError'>
See /var/log/up2date for more information


Actual results:
[root@vimappss-vrhel7 ~]# cat /var/log/up2date 
[Fri Nov 23 11:12:38 2018] up2date 
Traceback (most recent call last):
  File "/sbin/rhnreg_ks", line 215, in <module>
    cli.run()
  File "/usr/lib/python3.6/site-packages/up2date_client/rhncli.py", line 94, in run
    sys.exit(self.main() or 0)
  File "/sbin/rhnreg_ks", line 93, in main
    rhnreg.getCaps()
  File "/usr/lib/python3.6/site-packages/up2date_client/rhnreg.py", line 264, in getCaps
    s.capabilities.validate()
  File "/usr/lib/python3.6/site-packages/up2date_client/rhnserver.py", line 67, in __call__
    return rpcServer.doCall(method, *args, **kwargs)
  File "/usr/lib/python3.6/site-packages/up2date_client/rpcServer.py", line 214, in doCall
    ret = method(*args, **kwargs)
  File "/usr/lib64/python3.6/xmlrpc/client.py", line 1112, in __call__
    return self.__send(self.__name, args)
  File "/usr/lib/python3.6/site-packages/up2date_client/rpcServer.py", line 48, in _request1
    ret = self._request(methodname, params)
  File "/usr/lib/python3.6/site-packages/rhn/rpclib.py", line 394, in _request
    self._handler, request, verbose=self._verbose)
  File "/usr/lib/python3.6/site-packages/rhn/transports.py", line 153, in request
    connection = self.get_connection(host)
  File "/usr/lib/python3.6/site-packages/rhn/transports.py", line 333, in get_connection
    trusted_certs=self.trusted_certs)
  File "/usr/lib/python3.6/site-packages/rhn/connections.py", line 210, in __init__
    password, timeout=timeout)
  File "/usr/lib/python3.6/site-packages/rhn/connections.py", line 128, in __init__
    self._set_hostport(host, port)
<class 'AttributeError'>: 'HTTPSProxyConnection' object has no attribute '_set_hostport'



Expected results:


Additional info:
[root@vimappss-vrhel7 ~]# rpm -qa |egrep 'rhn|spacew'
python3-rhn-check-2.8.16-11.module+el8+2180+4b61dcd8.x86_64
rhn-setup-2.8.16-11.module+el8+2180+4b61dcd8.x86_64
rhn-client-tools-2.8.16-11.module+el8+2180+4b61dcd8.x86_64
dnf-plugin-spacewalk-2.8.5-7.module+el8+2180+4b61dcd8.noarch
rhn-check-2.8.16-11.module+el8+2180+4b61dcd8.x86_64
python3-rhn-setup-2.8.16-11.module+el8+2180+4b61dcd8.x86_64
rhnlib-2.8.6-5.module+el8+2180+4b61dcd8.noarch
python3-rhnlib-2.8.6-5.module+el8+2180+4b61dcd8.noarch
python3-rhn-client-tools-2.8.16-11.module+el8+2180+4b61dcd8.x86_64
python3-dnf-plugin-spacewalk-2.8.5-7.module+el8+2180+4b61dcd8.noarch
rhnsd-5.0.35-3.module+el8+2180+4b61dcd8.x86_64


Spacewalk Server is latest 2.8 running on rhel7