All vcs strategies support cached_download

bin/brew

@@ -81,7 +81,7 @@ begin
     if ARGV.named.empty?
       puts HOMEBREW_CACHE
     else
-      puts *ARGV.formulae.collect {|f| f.cached_download rescue '(built from source control)'}
+      puts *ARGV.formulae.collect {|f| f.cached_download}
     end
   when '--prefix'
     if ARGV.named.empty?