Remove unused variable

Remove unused variable clang complains about

Change-Id: I05ef90f45dbed0f51dace9c65a941f948fe579e7
Signed-off-by: Bernhard Rosenkränzer <Bernhard.Rosenkranzer@linaro.org>

services/core/jni/com_android_server_UsbDeviceManager.cpp

@@ -54,7 +54,7 @@ static void set_accessory_string(JNIEnv *env, int fd, int cmd, jobjectArray strA
     char buffer[256];
 
     buffer[0] = 0;
-    int length = ioctl(fd, cmd, buffer);
+    ioctl(fd, cmd, buffer);
     if (buffer[0]) {
         jstring obj = env->NewStringUTF(buffer);
         env->SetObjectArrayElement(strArray, index, obj);