create_local_printer(): Improved comparison of device URI host name

create_local_printer(): Improved comparison of device URI host name

Improved the comparison of the device URI host name with the CUPS
server's host name to find out whether the temporary queue is for a
local IPP service.

- Compare case-insensitively as host names are case-insensitive

- If we have the DNS-SD host name (DNSSDHostName) of the CUPS server,
  consider names equal if they only differ by the presence or absense
  of a trailing dot ('.')

- If we only have the ServerName (for example with "Browsing = Off",
  not sharing printers), consider also a server name without ".local"
  equal to a device URI host name with ".local" as equal.