Adding drag-state drawable to folder item icons.

Fixes b/8986628. Previously we had two states for
icons in the folder list (activated and default).
We now have a third state for when the app is in
drag mode and the folder is disabled which uses
a lighter grey icon. To make this work, we use
a custom drawable state (state_drag_mode) for
when drag is entered. Another CL will use this
new drag state for changing folder text color as well.

Change-Id: I280b187a454064f1c50f4ef62db5c8ba86c1f4d6
(cherry picked from commit 47fb86e95836e1a47bd784f6866c8c798b44ab6b)
diff --git a/Android.mk b/Android.mk
index a1c9cb6..1cf0bb6 100644
--- a/Android.mk
+++ b/Android.mk
@@ -39,7 +39,7 @@
 
 LOCAL_SRC_FILES := $(call all-java-files-under, $(src_dirs)) \
         $(call all-logtags-files-under, $(src_dirs))
-LOCAL_RESOURCE_DIR := $(addprefix $(LOCAL_PATH)/, $(res_dirs)) $(LOCAL_PATH)/res
+LOCAL_RESOURCE_DIR := $(addprefix $(LOCAL_PATH)/, $(res_dirs))
 LOCAL_AAPT_FLAGS := --auto-add-overlay
 LOCAL_AAPT_FLAGS += --extra-packages com.android.ex.chips:com.android.ex.photo