Add a missing error propagation
If the service returns a 504, we happily keep looping around and
retrying until we get a valid update.  Unfortunately, we missed the
else condition, which is what happens when this isn't a 504, leading
us to swallow real errors (500 and the like).  Trivial fix.
Fixes pulumi/pulumi#712.
@@ -424,6 +424,7 @@ func (b *cloudBackend) waitForUpdate(path string) (apitype.UpdateStatus, error)
time.Sleep(1 * time.Second)
continue
}
+ return apitype.StatusFailed, err
}
for _, event := range updateResults.Events {
