Check early that the config target exists and isn't a template

Reviewed-by: Andy Polyakov <appro@openssl.org>
(Merged from openssl#6885)

(cherry picked from commit 4e36044)

Author: levitte

Configure

@@ -911,11 +911,12 @@ if ($d) {
 	$target = $t;
     }
 }
+
+&usage if !$table{$target} || $table{$target}->{template};
+
 $config{target} = $target;
 my %target = resolve_config($target);
 
-&usage if (!%target || $target{template});
-
 my %conf_files = map { $_ => 1 } (@{$target{_conf_fname_int}});
 $config{conf_files} = [ sort keys %conf_files ];
 %target = ( %{$table{DEFAULTS}}, %target );