Changes.md: Change OUT_DIR to PRODUCT_OUT

"OUT" means "out/target/proudct/<product>/".
But "OUT_DIR" means "out/".
So we can't use "OUT_DIR" instead of "OUT".

We can use "PRODUCT_OUT" instead of "OUT" which means same folder.

Test: N/A Just document modification
Change-Id: Id08664ba48b226ead7ab6b00d0291259d3a737ba
diff --git a/Changes.md b/Changes.md
index c40d521..461de97 100644
--- a/Changes.md
+++ b/Changes.md
@@ -388,7 +388,7 @@
 
 | instead of                                                   | use                  |
 |--------------------------------------------------------------|----------------------|
-| OUT {#OUT}                                                   | OUT_DIR              |
+| OUT {#OUT}                                                   | PRODUCT_OUT          |
 | ANDROID_HOST_OUT {#ANDROID_HOST_OUT}                         | HOST_OUT             |
 | ANDROID_PRODUCT_OUT {#ANDROID_PRODUCT_OUT}                   | PRODUCT_OUT          |
 | ANDROID_HOST_OUT_TESTCASES {#ANDROID_HOST_OUT_TESTCASES}     | HOST_OUT_TESTCASES   |