[scenic] Remove duplicate package entry

Change-Id: I8a54ea059dd22dbd4f7891ea0fd7dd49e79d00a8
diff --git a/garnet/packages/tools/BUILD.gn b/garnet/packages/tools/BUILD.gn
index 59df7c5..f76d8ce 100644
--- a/garnet/packages/tools/BUILD.gn
+++ b/garnet/packages/tools/BUILD.gn
@@ -58,7 +58,6 @@
     "//garnet/packages/tools:netstack",
     "//garnet/packages/tools:runmany",
     "//garnet/packages/tools:scenic",
-    "//garnet/packages/tools:scenic",
     "//garnet/packages/tools:sl4f",
     "//garnet/packages/tools:tiles",
     "//garnet/packages/tools:wlan",