fake.rb.in: suppress warning

* template/fake.rb.in: suppress "assigned but unused variable"
  warning.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@50282 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

template/fake.rb.in

@@ -5,6 +5,7 @@ _=
 "`expr \"$ruby\" : echo > /dev/null || echo exec`" \
 "$ruby" '-r"`expr \"$0\" : / > /dev/null || pwd`/${0#/}" "$@";' \
 "}" || "exit" "$?"
+_=baseruby
 ruby=ruby
 class Object
   remove_const :CROSS_COMPILING if defined?(CROSS_COMPILING)