test: Use wget to test cockpit-ws port change

[stefwalter]

This is because on certain operating systems curl isn't up to
our strict standards of TLS we use in cockpit-ws.

[stefwalter]

Blockes #3138

[stefwalter]

Versions that used to work:

curl-7.29.0-25.el7.x86_64
nss-3.19.1-17.el7.x86_64

Versions that don't work:

curl-7.29.0-19.el7.x86_64
nss-3.19.1-7.el7_1.2.x86_64

The failure is:

[root@localhost ~]# curl -v -k https://localhost
* About to connect() to localhost port 443 (#0)
*   Trying ::1...
* Connected to localhost (::1) port 443 (#0)
* Initializing NSS with certpath: sql:/etc/pki/nssdb
* NSS error -12279 (SSL_ERROR_UNSUPPORTED_VERSION)
* Peer using unsupported version of security protocol.
* Error in TLS handshake, trying SSLv3...
> GET / HTTP/1.1
> User-Agent: curl/7.29.0
> Host: localhost
> Accept: */*
> 
...

[mvollmer]

We ran into this because I disabled the 'htb' repo when creating new RHEL images because $reasons. Whether or not we enable 'htb' in the long run, I think this change is good since it increases robustness of the test suite.