Answer the upgrade no-going-back prompt

For automated upgrade checks we need to ensure that the prompt
is answered, otherwise the upgrade will not go ahead.

Change-Id: I32e2b4554ef2fcf3fa2a8dead1ab5321fb392519

scripts/gate-check-commit.sh

@@ -154,8 +154,10 @@ if [[ "${ACTION}" == "upgrade" ]]; then
     # to bypass that for an automated test.
     export I_REALLY_KNOW_WHAT_I_AM_DOING=true
 
-    # Execute the upgrade script.
-    bash "$(dirname "${0}")/run-upgrade.sh"
+    # To execute the upgrade script we need to provide
+    # an affirmative response to the warning that the
+    # upgrade is irreversable.
+    echo 'YES' | bash "$(dirname "${0}")/run-upgrade.sh"
 
 fi