Log Message:
Update ruby-json and ruby-json-pure package to 1.5.4.

2011-08-31 (1.5.4)
  * Fix memory leak when used from multiple JRuby. (Patch by
    jfirebaugh@github).
  * Apply patch by Eric Wong <nocode@yhbt.net> that fixes garbage collection
    problem reported in https://github.com/flori/json/issues/46.
  * Add :quirks_mode option to parser and generator.
  * Add support for Rational and Complex number additions via json/add/complex
    and json/add/rational requires.