Add release flag logic based on TARGET_RELEASE.

Test: Lots of manual testing
Change-Id: I9072f136e64576009d0debd057c8ce6918fae861
diff --git a/envsetup.sh b/envsetup.sh
index 916344c..ef48249 100644
--- a/envsetup.sh
+++ b/envsetup.sh
@@ -842,7 +842,7 @@
     export TARGET_PRODUCT=$(get_build_var TARGET_PRODUCT)
     export TARGET_BUILD_VARIANT=$(get_build_var TARGET_BUILD_VARIANT)
     if [ -n "$release" ]; then
-      export TARGET_RELEASE=$(get_build_var TARGET_RELEASE)
+      export TARGET_RELEASE=$release
     else
       unset TARGET_RELEASE
     fi