Remove ruby 1.x compatiblity code
We no longer support running on Ruby 1.x so we can remove the workarounds.
Refs #26979 - Remove left over require
bf476d0ad900e36f25865592538942a4b91610ad removed lib/daemon.rb since
it only contained Ruby 1.x compatibility but left the require causing it
to fail to start up.
Refs #26979 - Require at least rack 1.3
This removes a workaround for an ancient rack version. EPEL7 contains
rack 1.6.4 so this should be safe.