Avoid calling 'hostname' which may not exist (and will probably
return "localhost" anyway").

diff -u -r ../fish-shell-master/share/functions/fish_prompt.fish ./share/functions/fish_prompt.fish
--- ../fish-shell-master/share/functions/fish_prompt.fish	2016-03-12 15:26:01.000000000 -0500
+++ ./share/functions/fish_prompt.fish	2016-03-13 17:49:30.550445275 -0400
@@ -5,7 +5,7 @@
 function fish_prompt --description "Write out the prompt"
 	# Just calculate this once, to save a few cycles when displaying the prompt
 	if not set -q __fish_prompt_hostname
-		set -g __fish_prompt_hostname (hostname|cut -d . -f 1)
+		set -g __fish_prompt_hostname "localhost"
 	end
 
 	set -l color_cwd