Tweak the BUILD file formatting.

Change-Id: I11b1c4b2bda836a9ea3afeb0cdf7aa9372eeaa13
Reviewed-on: https://code-review.googlesource.com/21991
Reviewed-by: Paul Wankadia <junyer@google.com>
diff --git a/BUILD b/BUILD
index 3a78ea9..dbc6a3d 100644
--- a/BUILD
+++ b/BUILD
@@ -10,7 +10,7 @@
 
 config_setting(
     name = "windows",
-    values = { "cpu": "x64_windows" },
+    values = {"cpu": "x64_windows"},
 )
 
 config_setting(