fix typo in default device location

"his English is a bit week"

Change-Id: Ic427290f905378e581fa2d6a58770a9be2a5588d
diff --git a/prod-tests/src/com/android/browser/tests/RandomUrlListPusher.java b/prod-tests/src/com/android/browser/tests/RandomUrlListPusher.java
index 461ab0e..b4b7f43 100644
--- a/prod-tests/src/com/android/browser/tests/RandomUrlListPusher.java
+++ b/prod-tests/src/com/android/browser/tests/RandomUrlListPusher.java
@@ -58,7 +58,7 @@
 
     @Option(name = "device-location",
             description = "location on device where the generate URL list should be pushed")
-    private String mDeviceLocation = "${EXTERNEL_STORAGE}/popular_urls.txt";
+    private String mDeviceLocation = "${EXTERNAL_STORAGE}/popular_urls.txt";
 
     @Override
     public void setUp(ITestDevice device, IBuildInfo buildInfo) throws TargetSetupError,