parser_none: Use faster record creation

[repeatedly]

Signed-off-by: Masahiro Nakagawa repeatedly@gmail.com

Which issue(s) this PR fixes:
None

What this PR does / why we need it:
I found current implementation is bit slower,

require 'benchmark/ips'

key = 'message'
value = 'loooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooong'

Benchmark.ips do |x|
  x.report "init" do
    r = {key => value}
  end

  x.report "init + []=" do
    r = {}
    r[key] = value
  end
end

Warming up --------------------------------------
                init   250.160k i/100ms
          init + []=   243.042k i/100ms
Calculating -------------------------------------
                init      5.944M (± 1.9%) i/s -     29.769M in   5.010006s
          init + []=      5.508M (± 1.2%) i/s -     27.707M in   5.031503s

Docs Changes:
No need.

Release Note:
Same title