Revert "Revert "Support filegroup in exclude_srcs""

This reverts commit 606e9de344fae07473dd79e5ac556886a72035de.

Reason for revert: <try to fix the broken build yesterday>

Change-Id: I2963b9af63c7c7398159e5e9a1e448266e1c81d5
Test: unittest
diff --git a/python/python.go b/python/python.go
index 9a3b1bb..ed879eb 100644
--- a/python/python.go
+++ b/python/python.go
@@ -266,11 +266,13 @@
 	android.ExtractSourcesDeps(ctx, p.properties.Data)
 	// deps from "srcs".
 	android.ExtractSourcesDeps(ctx, p.properties.Srcs)
+	android.ExtractSourcesDeps(ctx, p.properties.Exclude_srcs)
 
 	switch p.properties.Actual_version {
 	case pyVersion2:
 		// deps from "version.py2.srcs" property.
 		android.ExtractSourcesDeps(ctx, p.properties.Version.Py2.Srcs)
+		android.ExtractSourcesDeps(ctx, p.properties.Version.Py2.Exclude_srcs)
 
 		ctx.AddVariationDependencies(nil, pythonLibTag,
 			uniqueLibs(ctx, p.properties.Libs, "version.py2.libs",
@@ -286,6 +288,7 @@
 	case pyVersion3:
 		// deps from "version.py3.srcs" property.
 		android.ExtractSourcesDeps(ctx, p.properties.Version.Py3.Srcs)
+		android.ExtractSourcesDeps(ctx, p.properties.Version.Py3.Exclude_srcs)
 
 		ctx.AddVariationDependencies(nil, pythonLibTag,
 			uniqueLibs(ctx, p.properties.Libs, "version.py3.libs",