Make libbacktrace build with LLVM r275480

Bug: http://b/31320715

Test: No regression in 32-bit and 64-bit backtrace_test on host and
angler.

Change-Id: Ic5c5511e89ca7707ed9c13d5ba0539e09310dfe3
diff --git a/libbacktrace/BacktraceOffline.cpp b/libbacktrace/BacktraceOffline.cpp
index c2b68bc..a05a6d8 100644
--- a/libbacktrace/BacktraceOffline.cpp
+++ b/libbacktrace/BacktraceOffline.cpp
@@ -719,7 +719,7 @@
   auto binary_or_err = llvm::object::createBinary(buffer_or_err.get()->getMemBufferRef());
   if (!binary_or_err) {
     BACK_LOGW("failed to create binary for %s in %s: %s", elf_file.c_str(), apk_file.c_str(),
-              binary_or_err.getError().message().c_str());
+              llvm::toString(binary_or_err.takeError()).c_str());
     return nothing;
   }
   return llvm::object::OwningBinary<llvm::object::Binary>(std::move(binary_or_err.get()),