Drop 'sanity check'

Will clearly be needed for #40.

l3build-variables.lua

@@ -35,29 +35,6 @@ end
 module = module or ""
 bundle = bundle or ""
 
--- Sanity check
-if module == "" and bundle == "" then
-  if string.match(arg[0], "l3build%.lua$") then
-    print(
-      "\n" ..
-      "l3build: A testing and building system for LaTeX\n\n" ..
-      "Release " .. release_date
-    )
-    if arg[1] and not string.match(arg[1], "version") then
-      print(
-        "\n"
-          .. "Error: Call l3build using a configuration file, not directly.\n"
-      )
-    end
-  else
-    print(
-      "\n"
-        .. "Error: Specify either bundle or module in configuration script.\n"
-    )
-  end
-  exit(1)
-end
-
 -- Directory structure for the build system
 -- Use Unix-style path separators
 currentdir = "."