Revert the archive part of "Support/PathV2: Add identify_magic."

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123593 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Archive/ArchiveWriter.cpp b/lib/Archive/ArchiveWriter.cpp
index 8fcc7aa..07a9aaf 100644
--- a/lib/Archive/ArchiveWriter.cpp
+++ b/lib/Archive/ArchiveWriter.cpp
@@ -181,11 +181,9 @@
     flags |= ArchiveMember::HasPathFlag;
   if (hasSlash || filePath.str().length() > 15)
     flags |= ArchiveMember::HasLongFilenameFlag;
-
-  sys::LLVMFileType type;
-  if (sys::fs::identify_magic(mbr->path.str(), type))
-    type = sys::Unknown_FileType;
-  switch (type) {
+  std::string magic;
+  mbr->path.getMagicNumber(magic,4);
+  switch (sys::IdentifyFileType(magic.c_str(),4)) {
     case sys::Bitcode_FileType:
       flags |= ArchiveMember::BitcodeFlag;
       break;