Revert "[clang-doc] Updating BitcodeReader to use llvm::Error"

This reverts commit r339617 for breaking bots.

git-svn-id: https://llvm.org/svn/llvm-project/clang-tools-extra/trunk@339620 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed