Avoid talking about filter

Summary: In the past, there was an argument filter that got passed in. That got deleted a while ago, but the comment still mentions it, and we still splice the function `filter` into a string that doesn't require it. Clean that up.

Reviewed By: stepancheg

Differential Revision: D40215465

fbshipit-source-id: 05f0654d4a31f0cc5dba5101df65c3270d1538d6

shim/third-party/macros/rust_third_party.bzl

@@ -71,17 +71,14 @@ def _make_preamble(out_dir, package_name, version, features, cfgs, env, target_o
     )
 
 # Invoke a Rust buildscript binary with the right surrounding
-# environment variables. `filters` is a shell command which takes the
-# output of the build script and filters appropriately. It is given the
-# final output file path on its commandline.
+# environment variables.
 def rust_buildscript_genrule_filter(name, buildscript_rule, outfile, package_name, version, features = None, cfgs = None, env = None, target = None):
     pre = _make_preamble("\\$(dirname $OUT)", package_name, version, features, cfgs, env, target)
     native.cxx_genrule(
         name = name,
         out = outfile,
         cmd = pre + "$(exe {buildscript}) > $OUT".format(
             buildscript = buildscript_rule,
-            filter = filter,
         ),
     )