civetweb: update subproject

Fixes: #7786
Signed-off-by: Yehuda Sadeh <yehuda@inktank.com>

diff --git a/src/civetweb b/src/civetweb
index 041bebf7a3affe6700e72404dd159e35012b7990..438a4d0f58f8126a3e0d48860a7cd3c56a3c4659 160000 (submodule)
--- a/src/civetweb
+++ b/src/civetweb
@@ -1 +1 @@
-Subproject commit 041bebf7a3affe6700e72404dd159e35012b7990
+Subproject commit 438a4d0f58f8126a3e0d48860a7cd3c56a3c4659