Tests: unbreak dav tests on Perl < 5.12.

dav.t

diff --git a/dav.t b/dav.t
index 7083236..f01624a 100644
--- a/dav.t
+++ b/dav.t
@@ -119,6 +119,9 @@
 
 like($r, qr/201 Created.*(Content-Length|\x0d\0a0\x0d\x0a)/ms, 'mkcol');
 
+SKIP: {
+skip 'perl too old', 1 if !$^V or $^V lt v5.12.0;
+
 TODO: {
 local $TODO = 'not yet' unless $t->has_version('1.17.7');
 
@@ -126,6 +129,8 @@
 
 }
 
+}
+
 $r = http(<<EOF);
 COPY /test/ HTTP/1.1
 Host: localhost