Use bower paths relative to the domain

This is shorter, and makes it easier to move test files around.

Change-Id: Ife3dcdd66b66a698d71b0fce2bce457410a4dd73
diff --git a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.html b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.html
index 72fc1ee..287e983 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.html
+++ b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.html
@@ -15,7 +15,7 @@
 limitations under the License.
 -->
 
-<link rel="import" href="../../../bower_components/polymer/polymer.html">
+<link rel="import" href="/bower_components/polymer/polymer.html">
 <link rel="import" href="../../../behaviors/gr-patch-set-behavior/gr-patch-set-behavior.html">
 <link rel="import" href="../../../styles/shared-styles.html">
 <link rel="import" href="../../shared/gr-button/gr-button.html">