Fix server name used for display when under a path

When RTSERVER="http://rt.example.org/rt", bin/rt displays
    "Password will be sent to rt.example.orgrt"

Simplify the creation of $server, which is used only for display, to
only include the host and port.  Resolves [issues #22708]
Merge branch '4.0/rt-server-display-name' into 4.0-trunk