Update common-packer to v0.7.1

This fixes an issue with the builds not being able to find the
ca-ymq-2 availability zone.

Issue: LF-Jira RELENG-3344
Signed-off-by: Eric Ball <eball@linuxfoundation.org>
Change-Id: Id906600d10b67d55bddc616551dfe77ee3a37262

diff --git a/packer/common-packer b/packer/common-packer
index 6d13061..6485404 160000 (submodule)
--- a/packer/common-packer
+++ b/packer/common-packer
@@ -1 +1 @@
-Subproject commit 6d13061d653ffe84de00a904c6b49f4caaee2e30
+Subproject commit 6485404dda02505f48cef60d9aafd726c3aacfa8