(#10161) Parenthesize method arguments

Ruby 1.8.6 issues warnings when arguments to nested methods are not
parenthesized, e.g.

f.puts(YAML.dump metadata)

results in:

warning: parenthsize arguments(s) for future versions

These warnings were introduced during Windows development, but not
noticed on that platform due to using ruby 1.8.7, which doesn't issue
a warning. This commit just wraps the arguments in parenthesis.