sysupgrade: exit 1 instead of exit 0 when ending early

[Josh Grosse]

For ease of running sysupgrade from within a script.


diff --git a/usr.sbin/sysupgrade/sysupgrade.sh 
b/usr.sbin/sysupgrade/sysupgrade.sh
index d80ff127ffa..ce5800093c9 100644
--- a/usr.sbin/sysupgrade/sysupgrade.sh
+++ b/usr.sbin/sysupgrade/sysupgrade.sh
@@ -153,7 +153,7 @@ rm SHA256.sig
 
 if cmp -s /var/db/installed.SHA256 SHA256 && ! $FORCE; then
        echo "Already on latest snapshot."
-       exit 0
+       exit 1
 fi
 
 # INSTALL.*, bsd*, *.tgz