(FACT-695) Revert additions of number as types for memory facts

The previous commit for this ticket (merge commit c628fc48) converted
select memory facts to be floats, or in json: numbers. This makes
complete sense, but unfortunately broke acceptance tests on Solaris 11,
when using the Solaris runtime/ruby-18 package, which fails as follows
if serializing floats to json:

  ld.so.1: ruby: fatal: relocation error: file /var/ruby/1.8/gem_home/gems/json-1.8.1/lib/json/ext/generator.so: symbol isinf: referenced symbol not found