dont run network checks during upgrades since this is a bad reason to block an upgrade from going through

setup/start.sh

@@ -52,9 +52,13 @@ chmod +x /usr/local/bin/mailinabox
 source setup/questions.sh
 
 # Run some network checks to make sure setup on this machine makes sense.
+# Skip on existing installs since we don't want this to block the ability to
+# upgrade, and these checks are also in the control panel status checks.
+if [ -z "$DEFAULT_PRIMARY_HOSTNAME" ]; then
 if [ -z "$SKIP_NETWORK_CHECKS" ]; then
 	source setup/network-checks.sh
 fi
+fi
 
 # Create the STORAGE_USER and STORAGE_ROOT directory if they don't already exist.
 # If the STORAGE_ROOT is missing the mailinabox.version file that lists a