BinhostService/Get: Change package index to a relative path.

BUG=chromium:963528
TEST=run_tests

Change-Id: I1ac25e8d5cfe226e313d8eb5717023f7cd95f6a9
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/1651967
Tested-by: Alex Klein <saklein@chromium.org>
Reviewed-by: Evan Hernandez <evanhernandez@chromium.org>
diff --git a/api/controller/binhost.py b/api/controller/binhost.py
index 729026e..cf525da 100644
--- a/api/controller/binhost.py
+++ b/api/controller/binhost.py
@@ -39,7 +39,7 @@
   for current in binhosts:
     new_binhost = output_proto.binhosts.add()
     new_binhost.uri = current
-    new_binhost.package_index = binhost.GetPackageIndex(current)
+    new_binhost.package_index = 'Packages'
 
 
 def GetPrivatePrebuiltAclArgs(input_proto, output_proto):