Fix deprecation of Socket.gethostbyname

It appears on the output of OpenQA runs, for example this one:

https://openqa.opensuse.org/tests/4038465#step/rspec_webui_tests/11

dist/t/spec/support/capybara.rb

@@ -24,7 +24,7 @@
 
 # Set hostname
 begin
-  hostname = Socket.gethostbyname(Socket.gethostname).first
+  hostname = Addrinfo.getaddrinfo(Socket.gethostname).first
 rescue SocketError
   hostname = ''
 end