Support lib: use /samples directory. do not merge.

This NPW now looks for a "samples" directory at the root of
extras SDK packages. This renames the samples so they fit that
new pattern.

Content of the extra is thus:
/v4/*.jar
/v4/src/..
/v13/*.jar
/v13/src/..
/samples/Support4Demos/
/samples/Support13Demos/

(Cherry-pick from 913d903aa2480b387051ec41e6cd2580f7d72f96)

Change-Id: I4bb01d35ede7c7af45e80204c131361ffc4300ee
diff --git a/build/sdk.atree b/build/sdk.atree
index ef56eaf..038dafc 100644
--- a/build/sdk.atree
+++ b/build/sdk.atree
@@ -225,10 +225,11 @@
 sdk/files/sdk_files_NOTICE.txt                                                                    extras/android/support/NOTICE.txt
 ${OUT_DIR}/target/common/obj/PACKAGING/android-support-v4_intermediates/android-support-v4.jar    extras/android/support/v4/android-support-v4.jar
 frameworks/support/v4                                                                             extras/android/support/v4/src
-development/samples/Support4Demos                                                                 extras/android/support/v4/samples/Support4Demos
+development/samples/Support4Demos                                                                 extras/android/support/samples/Support4Demos
+
 ${OUT_DIR}/target/common/obj/PACKAGING/android-support-v13_intermediates/android-support-v13.jar  extras/android/support/v13/android-support-v13.jar
 frameworks/support/v13                                                                            extras/android/support/v13/src
-development/samples/Support13Demos                                                                extras/android/support/v13/samples/Support13Demos
+development/samples/Support13Demos                                                                extras/android/support/samples/Support13Demos
 
 development/sdk/prebuilt/v7                                                                       extras/android/support/v7