Trivial cleanups

• utils: Space out debugging messages a bit more

  Was: i386-linux-gnu-capsule-capture-libs: capture_one:We already have a symlink for libm.so.6

  Now: i386-linux-gnu-capsule-capture-libs: capture_one: We already have a symlink for libm.so.6

• library_cmp_filter_list: Move local variables into a narrower scope

  This makes it easier to reason about their valid lifetimes.

• library_cmp_filter_list: Automatically free buf at end of scope

/cc @refi64 @vivek