Description of problem:
If several SSL vhosts are sharing the same HTTPS port but have different TLS certificates, pulp-admin fails to verify the server's certificate.
Therefor SNI support for the admin client pulp-admin is required.
Steps to Reproduce:
1. Setup vhosts using the same HTTPS port with different certificates
2. login to pulp
3. enter "pulp-admin repo list"
pulp-admin throws an error, telling the common name does not match peer's name.
Moved to https://pulp.plan.io/issues/694