awesomerc.lua: use nano by default if no editor found in env

Signed-off-by: Julien Danjou <julien@danjou.info>

awesomerc.lua.in

@@ -9,8 +9,9 @@ require("beautiful")
 -- This is a file path to a theme file which will defines colors.
 theme_path = "@AWESOME_THEMES_PATH@/default"
 
--- This is used later as the default terminal to run.
+-- This is used later as the default terminal and editor to run.
 terminal = "xterm"
+editor = terminal .. " -e " .. os.getenv("EDITOR") or terminal .. " -e " .. "nano"
 
 -- Default modkey.
 -- Usually, Mod4 is the key with a logo between Control and Alt.
@@ -101,7 +102,7 @@ mytextbox.text = "<b><small> " .. AWESOME_RELEASE .. " </small></b>"
 -- Create a laucher widget and a main menu
 myawesomemenu = {
    {"manual", terminal .. " -e man awesome" },
-   {"edit config", terminal .. " -e " .. os.getenv("EDITOR") .. " " .. awful.util.getdir("config") .. "/rc.lua" },
+   {"edit config", editor .. " " .. awful.util.getdir("config") .. "/rc.lua" },
    {"restart", awesome.restart },
    {"quit", awesome.quit }
 }