* io.c (io_setstrbuf, io_read): should not shorten the given buffer until
read succeeds. [ruby-core:55951] [Bug #8625]
* io.c (read_all): truncate the buffer before appending read data,
instead of truncating before reading.
[ruby-core:55951] [Bug #8625]
merge revision(s) 46360,46372: [Backport #8625]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_0_0@46738 b2dd03c8-39d4-4d8f-98ff-823fe69b080e