Ruby

string.c: use the usable size

• string.c (rb_str_change_terminator_length): when called after
  the content has been copied, old terminator length no longer
  makes sense. use the whole usable size instead of capacity
  without terminator. [ruby-core:80257] [Bug #13339]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58042 b2dd03c8-39d4-4d8f-98ff-823fe69b080e