Install haveged package on 201911/stretch to accelerate the entropy collect process (#7308)

Recently, we found on some of our testbeds the entropy collecting process finishes more than 60 seconds after system started.
This results in swss not able to start sporadically.
To install haveged can accelerate the entropy collect process.

Signed-off-by: Stephen Sun <stephens@nvidia.com>

build_debian.sh

@@ -303,7 +303,8 @@ sudo LANG=C DEBIAN_FRONTEND=noninteractive chroot $FILESYSTEM_ROOT apt-get -y in
     makedumpfile            \
     conntrack               \
     python-pip              \
-    jq
+    jq                      \
+    haveged
 
 
 if [[ $CONFIGURED_ARCH == amd64 ]]; then