check if the platform is really the same, don't just take the existence of the...

check if the platform is really the same, don't just take the existence of the directory for sufficient

debian/aegir-provision.postinst

@@ -77,7 +77,7 @@ case "$1" in
             SITE=`grep URI $TEMPFILE | sed -e 's/^.*://'`
             OLD_PLATFORM=`grep 'Drupal root' $TEMPFILE | sed -e 's/^.*:[[:space:]]*//;s/[[:space:]]*$//'`
             NEW_PLATFORM="$VARLIB/hostmaster-$VERSION"
-            if [ -d "$NEW_PLATFORM" ]; then
+            if [ -d "$NEW_PLATFORM" ] && [ "$OLD_PLATFORM" = "$NEW_PLATFORM" ]; then
                 echo "it seems to be the same version as the one we're trying to install, not upgrading"
             else
                 echo "upgrading the frontend from $OLD_PLATFORM to $NEW_PLATFORM"