[LLVM-3.9] Replace NewArchiveIterator with NewArchiveMember
[LLVM-3.9] Replace NewArchiveIterator with NewArchiveMember

The new NewArchiveMember is simpler and requires less context,
according to upstream.

This was changed in http://reviews.llvm.org/D21721

graydon/rust,graydon/rust,GBGamer/rust,GBGamer/rust,aidancully/rust,graydon/rust,aidancully/rust,GBGamer/rust,GBGamer/rust,aidancully/rust,GBGamer/rust,aidancully/rust,GBGamer/rust,aidancully/rust,aidancully/rust,graydon/rust,GBGamer/rust,GBGamer/rust,graydon/rust,graydon/rust