Ensure that the pollSince is greater than Activation start time (#461)

This ensures that poll command does not repeatedly keep on fetching the last activation
diff --git a/commands/activation.go b/commands/activation.go
index 32aec98..0022016 100644
--- a/commands/activation.go
+++ b/commands/activation.go
@@ -402,7 +402,7 @@
 					reported[activation.ActivationID] = true
 				}
 				if activation.Start > pollSince {
-					pollSince = activation.Start
+					pollSince = activation.Start + 1
 				}
 			}
 			time.Sleep(time.Second * 2)