Fix #7375 regression in TensorBoard

WORKSPACE

@@ -480,7 +480,7 @@ new_http_archive(
 )
 
 new_http_archive(
-  name = "polymer_archive",
+  name = "polymer",
   build_file = "bower.BUILD",
   url = "https://github.com/polymer/polymer/archive/v1.7.0.tar.gz",
   strip_prefix = "polymer-1.7.0",

tensorflow/tensorboard/bower/BUILD

@@ -65,7 +65,7 @@ filegroup(
         "@paper_toolbar//:paper_toolbar",
         "@paper_tooltip//:paper_tooltip",
         "@plottable//:plottable",
-        "@polymer_archive//:polymer",
+        "@polymer//:polymer",
         "@promise_polyfill//:promise_polyfill",
         "@three_js_orbitcontrols_js//file",
         "@three_js_three_min_js//file",