Fix test break due to API not working as advertised.

The API documentation has been improved in a separate change.

bug: 18587205

Change-Id: Ic7b624a552ee11cc7109d646bffae9c99787db37
diff --git a/tests/core/runner/src/com/android/cts/runner/CtsTestRunListener.java b/tests/core/runner/src/com/android/cts/runner/CtsTestRunListener.java
index 5f67475..57945f8 100644
--- a/tests/core/runner/src/com/android/cts/runner/CtsTestRunListener.java
+++ b/tests/core/runner/src/com/android/cts/runner/CtsTestRunListener.java
@@ -160,6 +160,7 @@
             mHostnameVerifier = HttpsURLConnection.getDefaultHostnameVerifier();
             mSslSocketFactory = HttpsURLConnection.getDefaultSSLSocketFactory();
 
+            mProperties.setProperty("user.home", "");
             mProperties.setProperty("java.io.tmpdir", System.getProperty("java.io.tmpdir"));
             // The CDD mandates that devices that support WiFi are the only ones that will have 
             // multicast.