soong: Add `aapt_version_code` default

This appends  to aapt flags, which is
useful for flushing some caches upon system updates.

Change-Id: I4ae1a1939f97f9ce6bb821b0b5687ad48e8ea343
diff --git a/build/soong/Android.bp b/build/soong/Android.bp
index bded9c0..e83fdb9 100644
--- a/build/soong/Android.bp
+++ b/build/soong/Android.bp
@@ -51,6 +51,26 @@
 
 // Target platform agnostic config modules
 soong_config_module_type {
+    name: "aapt_version_code",
+    module_type: "java_defaults",
+    config_namespace: "blissGlobalVars",
+    value_variables: ["aapt_version_code"],
+    properties: ["aaptflags"],
+}
+
+aapt_version_code {
+    name: "aapt_version_code_defaults",
+    soong_config_variables: {
+        aapt_version_code: {
+            aaptflags: [
+                "--version-code",
+                "%s",
+            ],
+        },
+    },
+}
+
+soong_config_module_type {
     name: "gralloc_10_usage_bits",
     module_type: "cc_defaults",
     config_namespace: "blissGlobalVars",