branch: b1_6

fix test script: at_start return correct value.
b=13659
r=grev

lustre/tests/replay-single.sh

@@ -1385,7 +1385,7 @@ AT_MAX_SET=0
 
 at_start()
 {
-    at_is_valid || skip "AT env is invalid"
+    at_is_valid || { skip "AT env is invalid" && return 1 }
 
     if ! at_is_enabled; then
         echo "AT is disabled, enable it by force temporarily"