[lib/Object] - Fix build bot after r303331 "[lib/Object] - Minor API update...

[lib/Object] - Fix build bot after r303331 "[lib/Object] - Minor API update for llvm::Decompressor".

Error was:
Decompressor.h:33:28: error: extra qualification ‘llvm::object::Decompressor::’ on member ‘resizeAndDecompress’ [-fpermissive]
   template <class T> Error Decompressor::resizeAndDecompress(T &Out) {

llvm-svn: 303334