FS-9258: Recursive calls to $.verto.rpcClient.speedTest() don't work

Assigning the speedTest callback funtion to a local variable and unsetting
the this.speedCB instance variable prior to calling the callback function
allows the rpcClient.speedTest functionality to be used more creatively
(such as calling it recursively for multiple runs) without affecting existing
functionality.

html5/verto/js/src/jquery.jsonrpcclient.js

@@ -429,8 +429,14 @@
 		var down_kps = (((this.speedBytes * 8) / (this.down_dur / 1000)) / 1024).toFixed(0);
 		
 		console.info("Speed Test: Up: " + up_kps + " Down: " + down_kps);
-		this.speedCB(event, { upDur: this.up_dur, downDur: this.down_dur, upKPS: up_kps, downKPS: down_kps });
+		var cb = this.speedCB;
 		this.speedCB = null;
+		cb(event, {
+			upDur: this.up_dur,
+			downDur: this.down_dur,
+			upKPS: up_kps,
+			downKPS: down_kps
+		});
 	    }
 	    
 	    return;