python: Name the GC timeout

So that it can show up with its own name in profiling outputs.

https://bugzilla.gnome.org/show_bug.cgi?id=726327
python: Fix coding style to match

Commit 2680b37802f0364b6eac1f5bf0f1f3bbb2552133 didn't use the
same coding style as the rest of the file.