fabfile: more deps for building perf

Signed-off-by: Sage Weil <sage@inktank.com>
build-ceph-deb-native: include libleveldb1 backport in precise repo

If libleveldb1 is on the build machine, include it in the genearted repo.
This isn't super elegant, but it works.

Signed-off-by: Sage Weil <sage@inktank.com>