Fix PR#193.

Fix PR#193.

Modified ReadArchiveBuffer() so that it dynamically allocates the
std::string object used to hold the bytecode object file's name.  This is
necessary because it is passed by reference to the new Module that is
allocated to represent the bytecode object, and previously we were
using a std::string that disappeared on function exit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@10565 91177308-0d34-0410-b5e6-96231b3b80d8