Updated 2.0-stable omnibus with downgraded FPM

FPM 1.0.0+ uses FFI to attach to some `libc` functions. This logic is
completely broken on RHEL 5 & 6. As we don’t need a bleeding edge FPM
the easiest fix is to just downgrade to the most recent pre-1.0.0
version.

This change has been tested in CI:
http://wilson.ci.opscode.us/job/chef-server-trigger-ad_hoc/1/downstreambuildview/

/cc @opscode/server-team @opscode/release-engineers