Remove references to build_with_libjingle and libjingle_java GYP variables.

webrtc/examples/androidapp/README

 This directory contains an example Android client for https://apprtc.appspot.com
 
 Prerequisites:
 - "Getting the code" on http://www.webrtc.org/native-code/android
 - Set up webrtc-related GYP variables:
-  export GYP_DEFINES="build_with_libjingle=1 build_with_chromium=0 libjingle_java=1
-  OS=android $GYP_DEFINES"
-  To cause WEBRTC_LOGGING to emit to Android's logcat, add enable_tracing=1 to
-  the $GYP_DEFINES above.
+  export GYP_DEFINES="OS=android $GYP_DEFINES"
 - When targeting both desktop & android, make sure to use a different output_dir
   value in $GYP_GENERATOR_FLAGS - for example
   export GYP_GENERATOR_FLAGS="$GYP_GENERATOR_FLAGS output_dir=out_android"
   or you'll likely end up with mismatched ARM & x86 output artifacts.
   If you use an output_dir other than out/ make sure to modify the command-lines
   below appropriately.
 - Finally, run "gclient runhooks" to generate Android-targeting .ninja files.
 
 Example of building & using the app:
 
 cd <path/to/webrtc>/src
 ninja -C out/Debug AppRTCDemo
 adb install -r out/Debug/apks/AppRTCDemo.apk
 
 In desktop chrome, navigate to https://apprtc.appspot.com and note the r=<NNN> room
 this redirects to or navigate directly to https://apprtc.appspot.com/r/<NNN> with
 your own room number. Launch AppRTC on the device and add same <NNN> into the room name list.
 
 You can also run application from a command line to connect to the first room in a list:
 adb shell am start -n org.appspot.apprtc/.ConnectActivity -a android.intent.action.VIEW
 This should result in the app launching on Android and connecting to the 3-dot-apprtc
 page displayed in the desktop browser.
 To run loopback test execute following command:
 adb shell am start -n org.appspot.apprtc/.ConnectActivity -a android.intent.action.VIEW --ez "org.appspot.apprtc.LOOPBACK" true