Remove duplicate SHA1 variable in js.bzl

Change-Id: Id9f8e724fdf62ea482a240561a78e9034248419d
diff --git a/tools/bzl/js.bzl b/tools/bzl/js.bzl
index d110f3e..77ac71b 100644
--- a/tools/bzl/js.bzl
+++ b/tools/bzl/js.bzl
@@ -21,7 +21,7 @@
   """rule to download a NPM archive."""
   name = ctx.name
   version= NPM_VERSIONS[name]
-  sha1 = NPM_VERSIONS[name]
+  sha1 = NPM_SHA1S[name]
 
   dir = '%s-%s' % (name, version)
   filename = '%s.tgz' % dir
@@ -38,7 +38,6 @@
   python = ctx.which("python")
   script = ctx.path(ctx.attr._download_script)
 
-  sha1 = NPM_SHA1S[name]
   args = [python, script, "-o", dest, "-u", url, "-v", sha1]
   out = ctx.execute(args)
   if out.return_code: