Use external/bvb instead of system/bvb in the manifests.

This repository holds the code related to Brillo Verified Boot.

BUG=29099910

Change-Id: Ia0573b30a354cfd39420bbba6fb3c2b26ee9af87
diff --git a/default.xml b/default.xml
index d470328..e21861a 100644
--- a/default.xml
+++ b/default.xml
@@ -48,6 +48,7 @@
   <project path="external/bison" name="platform/external/bison" groups="bdk" />
   <project path="external/boringssl" name="platform/external/boringssl" groups="bdk" />
   <project path="external/bsdiff" name="platform/external/bsdiff" groups="bdk" />
+  <project path="external/bvb" name="platform/external/bvb" groups="bdk" />
   <project path="external/bzip2" name="platform/external/bzip2" groups="bdk" />
   <project path="external/c-ares" name="platform/external/c-ares" groups="bdk" />
   <project path="external/chromite" name="platform/external/chromite" groups="bdk" />
@@ -159,7 +160,6 @@
   <project path="prebuilts/sdk" name="platform/prebuilts/sdk" groups="bdk" />
   <project path="prebuilts/tools" name="platform/prebuilts/tools" groups="tools,bdk" />
   <project path="system/bt" name="platform/system/bt" groups="bdk" />
-  <project path="system/bvb" name="platform/system/bvb" groups="bdk" />
   <project path="system/ca-certificates" name="platform/system/ca-certificates" groups="bdk" />
   <project path="system/connectivity/apmanager" name="platform/system/connectivity/apmanager" groups="bdk" />
   <project path="system/connectivity/shill" name="platform/system/connectivity/shill" groups="bdk" />