CLOUDSTACK-7143: fix a missing apt-get update

In 8e2d06153b3d5ec1540fac1c8fbc97b5d2b58a8e I mistakenly/accidentally
a apt-get update.

As
    https://wiki.debian.org/Multiarch/HOWTO
explains, apt-get update is needed after adding a new architecture.

tools/appliance/definitions/systemvmtemplate/install_systemvm_packages.sh

@@ -47,6 +47,7 @@ function install_packages() {
   #32 bit architecture support:: not required for 32 bit template
   if [ "${arch}" != "i386" ]; then
     dpkg --add-architecture i386
+    apt-get update
     ${apt_install} links:i386 libuuid1:i386
   fi