xrefs: Update access of env var

Bug: 600
Change-Id: I3f49886c48b005015894577df5e643630e44264d
Reviewed-on: https://pigweed-review.googlesource.com/c/infra/recipes/+/81020
Pigweed-Auto-Submit: Rob Mohr <mohrr@google.com>
Reviewed-by: Ted Pudlik <tpudlik@google.com>
Commit-Queue: Auto-Submit <auto-submit@pigweed.google.com.iam.gserviceaccount.com>
diff --git a/recipes/xrefs.py b/recipes/xrefs.py
index 890ab9f..610190b 100644
--- a/recipes/xrefs.py
+++ b/recipes/xrefs.py
@@ -50,7 +50,7 @@
     # just use a stand-in path when it isn't set.
     try:
         api.kythe.kythe_dir = api.path.abs_to_path(
-            api.environment.PW_PIGWEED_CIPD_INSTALL_DIR
+            env.PW_PIGWEED_CIPD_INSTALL_DIR
         ).join('kythe')
     except AttributeError:
         api.kythe.kythe_dir = api.path['start_dir'].join('kythe')