storagestruct.Machine duplicates storagestructs.Platform in a bad way

We have:
struct Platform {
    1: optional OS os
    2: optional OSVersion osVersion
    3: optional Architecture arch
    4: optional Compiler compiler
}

and now:

struct Machine {
    1: optional OS os
    2: optional OSVersion os_version
    3: optional string arch // x86 or x86_64
    4: optional Compiler compiler
}

Which is an inferior copy of the first. We should have turned the string into an enum first and used Platform everywhere.

This should be cleaned up.