pw_env_setup: Better error message for CIPD download

Change-Id: I7d76b829bea474b86b0493593bbfcb9aac6b8303
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/38920
Commit-Queue: Auto-Submit <auto-submit@pigweed.google.com.iam.gserviceaccount.com>
Pigweed-Auto-Submit: Rob Mohr <mohrr@google.com>
Reviewed-by: Ewout van Bekkum <ewout@google.com>
diff --git a/pw_env_setup/py/pw_env_setup/cipd_setup/wrapper.py b/pw_env_setup/py/pw_env_setup/cipd_setup/wrapper.py
index 572f4ab..95c2afe 100755
--- a/pw_env_setup/py/pw_env_setup/cipd_setup/wrapper.py
+++ b/pw_env_setup/py/pw_env_setup/cipd_setup/wrapper.py
@@ -243,7 +243,8 @@
         else:
             break
 
-    raise Exception('failed to download client')
+    raise Exception('failed to download client from https://{}{}'.format(
+        CIPD_HOST, path))
 
 
 def bootstrap(client, silent=('PW_ENVSETUP_QUIET' in os.environ)):