Updated git submodules

Project: netvirt master 648861894b7e36fdcef028e991cffdd416d63811

Clean up Optional uses

This patch reverts Optional and related streaming uses where they
result in more convoluted code than necessary (or, in the case of
Optional, where Optional instances are created only for conditions).

Change-Id: I8d0b2c456ff0a477e440fb029b8495476aabed27
Signed-off-by: Stephen Kitt <skitt@redhat.com>

diff --git a/docs/submodules/netvirt b/docs/submodules/netvirt
index cd8f85bb86ef6549f4e0251ceae49e3c520278f2..648861894b7e36fdcef028e991cffdd416d63811 160000 (submodule)
--- a/docs/submodules/netvirt
+++ b/docs/submodules/netvirt
@@ -1 +1 @@
-Subproject commit cd8f85bb86ef6549f4e0251ceae49e3c520278f2
+Subproject commit 648861894b7e36fdcef028e991cffdd416d63811