Bio::Index::Abstract->_type_and_version: check type before version (i…

…ssue #281)

Because each index uses its own version number, there's no point in
checking the version number before we know the type is correct.  So
test type first, and only then test the version number.

Bio/Index/Abstract.pm

@@ -490,10 +490,10 @@ sub _type_and_version {
 	# Run check or add type and version key if missing
 	if (my $rec = $self->db->{ $key }) {
 		my( $db_type, $db_version ) = $self->unpack_record($rec);
-		$self->throw("This index file is from version [$db_version] - You need to rebuild it to use module version [$version]")
-		  unless $db_version == $version;
 		$self->throw("This index file is type [$db_type] - Can't access it with module for [$type]")
 		  unless $db_type eq $type;
+		$self->throw("This index file is from version [$db_version] - You need to rebuild it to use module version [$version]")
+		  unless $db_version == $version;
 	} else {
 		$self->add_record( $key, $type, $version )
 		  or $self->throw("Can't add Type and Version record");