Update the bug that's blocking libc++fs for vendor code.
We're still working on it, but having a bug that's already been closed
in the comment makes it look like this is actually ready.
diff --git a/Android.bp b/Android.bp
index 2686464..e29a44c 100644
@@ -195,7 +195,7 @@
// Not available to vendor modules until libc++ is updated and this library is
// merged into libc++ proper.
+// Follow http://b/175635923 for progress.