<rdar://problem/11374963>

When attaching on ARM hosted debuggers we were incorrectly setting the triple to "arm-apple-ios". This was happening because in the post attach code, we would lookup the process info through the platform, and if successful, we would get the architecture of the process. This code uses sysctl() calls, but we can only get the CPU type, not the subtype, so we would get ARM for CPU type and nothing for the cpu subtype, so this would map to "arm-apple-ios". I fixed the code to get the cpu subtype from "hw.cpusubtype" which is what we really want for ARM, and not the architecture is already correct. "add-dsym" then works like a charm. I also improved the command output when the architecture changes to show the entire triple instead of just the arch name.

llvm-svn: 163868