Miss USB device Interface from UsbManager.getDeviceList().

In the scenario that you connect more than one device to android phone
with an usb hub, when you attach the second device,mNewConfigurationis
is still corresponded to the first device unless another
mNewConfiguration is created by a new operation. However,before another
mNewConfiguration is created,setInterfaces() in addUsbConfiguration()
has already been executed. Problem is that mNewInterfaces has already
been cleared when it finished endUsbDeviceAdded for the first device. As
a result,the UsbInterface descriptor in the first device's Configuration
descriptor is set to null.

Bug: 22657587

Change-Id: I0ba4f07c809d07ebebed633e43c3ee8e2e4c5060
diff --git a/services/usb/java/com/android/server/usb/UsbHostManager.java b/services/usb/java/com/android/server/usb/UsbHostManager.java
index 6300a9a..965341e 100644
--- a/services/usb/java/com/android/server/usb/UsbHostManager.java
+++ b/services/usb/java/com/android/server/usb/UsbHostManager.java
@@ -231,6 +231,8 @@
             mNewConfigurations = null;
             mNewInterfaces = null;
             mNewEndpoints = null;
+            mNewConfiguration = null;
+            mNewInterface = null;