Add common directory to BasicSyncAdapter sample

This directory will be automatically copied over using a
templating system in the future, but for now it needs to
be copied in using sdk.atree.

This also allows us to remove the symlink that was checked
in previously, and which likely won't work on Windows.

Change-Id: If3d78eec7c1b845d1ae1caca59099d3284bdf73a
diff --git a/build/sdk.atree b/build/sdk.atree
index 5f7a272..c3c782a 100644
--- a/build/sdk.atree
+++ b/build/sdk.atree
@@ -187,7 +187,11 @@
 #
 
 # New sample tree
+# Note: Some samples reference a shared "common" directory. In the future
+# this will be copied in automatically via a templating system. For now,
+# we need to copy it in here as needed.
 developers/samples/android/connectivity        samples/${PLATFORM_NAME}/connectivity
+developers/samples/android/common              samples/${PLATFORM_NAME}/connectivity/sync/BasicSyncAdapter/BasicSyncAdapter/src/main/java/com/example/android/common
 developers/samples/android/content             samples/${PLATFORM_NAME}/content
 developers/samples/android/input               samples/${PLATFORM_NAME}/input
 developers/samples/android/media               samples/${PLATFORM_NAME}/media