title: Locator Strategy 'css selector' is not supported for this session issue with appium
body: <p>Since I'm new to mobile automation, I've been trying to run simple activities using appium maven and eclipse. But When I try to run Calculator app opens but the elements are not accessible.</p>
  
  <p>This the code I used to run a simple calculator</p>
  
  <pre><code>  @BeforeClass
   public void setUp() throws MalformedURLException {
  
      DesiredCapabilities capabilities = new DesiredCapabilities();
      capabilities.setCapability("BROWSER_NAME", "Android");
      capabilities.setCapability("VERSION", "4.4.2");
      capabilities.setCapability("deviceName", "Emulator");
      capabilities.setCapability("platformName", "Android");
  
      capabilities.setCapability("appPackage", "com.android.calculator2");
  
      capabilities.setCapability("appActivity", "com.android.calculator2.Calculator");
  
      driver = new RemoteWebDriver(new URL("http://0.0.0.0:4723/wd/hub"), capabilities);
  }
  
  @Test
  public void testCal() throws Exception {
  
      WebElement two = driver.findElement(By.name("2"));
      two.click();
  
  }
  
  @AfterClass
  public void teardown() {
  
  }
  </code></pre>
  
  <p><strong>I am using the latest stable dependencies.</strong>
      io.appium java-client 7.0.0 and 
  org.testng testng 6.14.3 </p>
  
  <pre><code>FAILED: testCal
  org.openqa.selenium.InvalidSelectorException: Locator Strategy 'css 
  selector' is not supported for this session
  For documentation on this error, please visit: 
  https://www.seleniumhq.org/exceptions/invalid_selector_exception.html
  Driver info: org.openqa.selenium.remote.RemoteWebDriver
  Capabilities {BROWSER_NAME: Android, VERSION: 4.4.2, appActivity: 
  com.android.calculator2.Cal..., appPackage: com.android.calculator2, 
  databaseEnabled: false, desired: {BROWSER_NAME: Android, VERSION: 4.4.2, 
  appActivity: com.android.calculator2.Cal..., appPackage: 
  com.android.calculator2, deviceName: Emulator, platformName: android}, 
  deviceManufacturer: HUAWEI, deviceModel: FLA-LX2, deviceName: 
  HXT7N18521000819, deviceScreenSize: 1080x2160, deviceUDID: 
  HXT7N18521000819, javascriptEnabled: true, locationContextEnabled: false, 
  networkConnectionEnabled: true, platform: LINUX, platformName: LINUX, 
  platformVersion: 8.0.0, takesScreenshot: true, warnings: {}, 
  webStorageEnabled: false}
  Session ID: a604a166-3c0d-4e9c-a3e4-9b1ea734bee6
  *** Element info: {Using=name, value=2}
  at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
  at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
  at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown 
  Source)
  at java.lang.reflect.Constructor.newInstance(Unknown Source)
  at...
  </code></pre>