Revert "Remove the redundant dependency on Support7Demos"

This reverts commit 12edcb5d03e99734b025e8b8f970cabc9b291cd3.

Change-Id: Ie9ab4114afb2a674fdfd2bae535ebac8e18a5ec9
diff --git a/samples/SupportDesignDemos/Android.mk.disabled b/samples/SupportDesignDemos/Android.mk
similarity index 100%
rename from samples/SupportDesignDemos/Android.mk.disabled
rename to samples/SupportDesignDemos/Android.mk