t/httpd-corner.t: fix uninitialized warning

Current versions of Perl don't warn when vec() is given `undef'
as its first arg, but Perl 5.10.1 does, at least.

Fixes: c7b4cbdadf3116a0 ("t/httpd-corner: improve reliability and diagnostics")

1 files changed, 1 insertions, 1 deletions

diff --git a/t/httpd-corner.t b/t/httpd-corner.t
index 7a6bcc66..68148655 100644
--- a/t/httpd-corner.t
+++ b/t/httpd-corner.t
@@ -296,7 +296,7 @@ my $len = length $str;
 is($len, 26, 'got the alphabet');
 my $check_self = sub {
         my ($conn) = @_;
-        vec(my $rbits, fileno($conn), 1) = 1;
+        vec(my $rbits = '', fileno($conn), 1) = 1;
         select($rbits, undef, undef, 30) or Carp::confess('timed out');
         $conn->read(my $buf, 4096);
         my ($head, $body) = split(/\r\n\r\n/, $buf, 2);