Fixed a typo (#3218)

* Fixed a typo

* Remove outdated url link.

apps/android_rpc/README.md

@@ -141,7 +141,7 @@ export TVM_NDK_CC=/opt/android-toolchain-arm64/bin/aarch64-linux-android-g++
 python android_rpc_test.py
 ```
 
-This will compile TVM IR to shared libraries (CPU, OpenCL and Vulkan) and run vector addition on your Android device. To verify compiled TVM IR shared libraries on OpenCL target set [`'test_opencl = True'`](https://github.com/dmlc/tvm/blob/master/apps/android_rpc/tests/android_rpc_test.py#L25) and on Vulkan target set [`'test_vulkan = False'`](https://github.com/dmlc/tvm/blob/master/apps/android_rpc/tests/android_rpc_test.py#L27) in  [tests/android_rpc_test.py](https://github.com/dmlc/tvm/blob/master/apps/android_rpc/tests/android_rpc_test.py), by default on CPU target will execute.
+This will compile TVM IR to shared libraries (CPU, OpenCL and Vulkan) and run vector addition on your Android device. To verify compiled TVM IR shared libraries on OpenCL target set `'test_opencl = True'` and on Vulkan target set `'test_vulkan = True'` in  [tests/android_rpc_test.py](https://github.com/dmlc/tvm/blob/master/apps/android_rpc/tests/android_rpc_test.py), by default on CPU target will execute.
 On my test device, it gives following results.
 
 ```bash