Updated git submodules

Project: releng/builder master 671c7f131175e352b227021ecb851c3936857297

Fix default mininet image name

Most of csit jobs are currently failing to create tools system VM.
This is a quick fix to use 25 version as the default.
Jobs who use mininet application may not expect this newer version,
but most of csit jobs are using tools system for other things than mininet.

Change-Id: I105551d5a5912be1ecb1db5172faa3c9863bc286
Signed-off-by: Vratko Polak <vrpolak@cisco.com>

diff --git a/docs/submodules/releng/builder b/docs/submodules/releng/builder
index 5b1f8846f413f03b311bcb0a260f37f9a02083e7..671c7f131175e352b227021ecb851c3936857297 160000 (submodule)
--- a/docs/submodules/releng/builder
+++ b/docs/submodules/releng/builder
@@ -1 +1 @@
-Subproject commit 5b1f8846f413f03b311bcb0a260f37f9a02083e7
+Subproject commit 671c7f131175e352b227021ecb851c3936857297