appliance: before apt-get upgrade, do a clean to free-up space

Signed-off-by: Rohit Yadav <rohit.yadav@shapeblue.com>

tools/appliance/definitions/systemvm64template/postinstall.sh

@@ -110,6 +110,7 @@ install_packages() {
   apt-get --no-install-recommends -q -y --force-yes install radvd
 
   # do a final update and upgrade
+  apt-get clean
   apt-get update
   apt-get -y --force-yes upgrade
 }

tools/appliance/definitions/systemvmtemplate/postinstall.sh

@@ -100,6 +100,7 @@ install_packages() {
   apt-get --no-install-recommends -q -y --force-yes install radvd
 
   # do a final update and upgrade
+  apt-get clean
   apt-get update
   apt-get -y --force-yes upgrade
 }