Revert r371023 "[lib/ObjectYAML] - Stop calling error(1) when mapping the...

Revert r371023 "[lib/ObjectYAML] - Stop calling error(1) when mapping the st_other field of a symbol."

It broke BBots:

http://lab.llvm.org:8011/builders/lld-x86_64-darwin13/builds/36387/steps/build_Lld/logs/stdio
http://lab.llvm.org:8011/builders/clang-x86_64-debian-fast/builds/17117/steps/test/logs/stdio

llvm-svn: 371024