Tests: fix typo in fastcgi test.
diff --git a/fastcgi.t b/fastcgi.t
index 9b87a99..9ff4e5b 100644
--- a/fastcgi.t
+++ b/fastcgi.t
@@ -24,7 +24,7 @@
 select STDOUT; $| = 1;
 
 eval { require FCGI; };
-plain(skip_all => 'FCGI not installed') if $@;
+plan(skip_all => 'FCGI not installed') if $@;
 
 my $t = Test::Nginx->new()->plan(3)
 	->write_file_expand('nginx.conf', <<'EOF');