Update common-packer to the latest v0.7.6

Change-Id: If2e18ee55aefd6fd4d1e4ff966d7244303441bda
Issue-ID: CIMAN-33
Signed-off-by: Anil Belur <abelur@linuxfoundation.org>

diff --git a/packer/common-packer b/packer/common-packer
index 38f8109..74b6be7 160000 (submodule)
--- a/packer/common-packer
+++ b/packer/common-packer
@@ -1 +1 @@
-Subproject commit 38f810974c2fdb9b4eb998b5efee93362904cced
+Subproject commit 74b6be7301b5c407d1ccf4cf6093b3b8cd308ad7