fix(http): set isForceSampled based on mustCollect

Author: gergelyke

lib/providers/httpTransaction/index.js

@@ -153,7 +153,7 @@ HttpTransaction.prototype.onServerSend = function (data) {
 
   var isSampled = trace.isSampled || (1 / this.sampleRate) > Math.random();
   if (data.mustCollect || isSampled) {
-    trace.isForceSampled = !!trace.isSampled;
+    trace.isForceSampled = !!data.mustCollect;
     delete trace.isSampled;
 
     this.traces.push(trace);