Fix a bug in SimpleConditionTracker.

copy-paste bug

Test: manual. Will add unit tests for it.
Change-Id: I9494271a8a407b0f3c5fc0138c1afb4925c69b79
diff --git a/cmds/statsd/src/condition/SimpleConditionTracker.cpp b/cmds/statsd/src/condition/SimpleConditionTracker.cpp
index 14ec72e..e78c0de 100644
--- a/cmds/statsd/src/condition/SimpleConditionTracker.cpp
+++ b/cmds/statsd/src/condition/SimpleConditionTracker.cpp
@@ -58,7 +58,7 @@
             return;
         }
         mStopLogMatcherIndex = pair->second;
-        mTrackerIndex.insert(mStartLogMatcherIndex);
+        mTrackerIndex.insert(mStopLogMatcherIndex);
     } else {
         mStopLogMatcherIndex = -1;
     }