[gold patch] Fix problem where --incremental-base with huge file reports "file too short"

[Cary Coutant]

>> 2011-10-11  Cary Coutant  <ccoutant@google.com>
>>
>>       * gold/output.cc (Output_file::open_base_file): Handle case where
>>       ::read returns less than requested size.
>
> This is OK.

Thanks, committed.

-cary