ObsoleteFiles: move libelf.so.2 to MOVED_LIBS

5a536241ea2b moved it from /usr/lib to /lib. This case is now handled
using MOVED_LIBS.

Reported by: dim
Sponsored by: The FreeBSD Foundation

(cherry picked from commit 42818aba8d4d5212b3b536f52b9f4e3559d091b7)