apt: pass child process stdout and stdout to m.fail_json() and m.exit_json().

Without this, this fails:

    - name: apt-get dist-upgrade
      action: apt upgrade=dist
      register: apt_get_contents

    - name: apt-get clean
      action: command apt-get clean
      when: apt_get_contents.stdout.find("0 upgraded") == -1

TASK: [apt-get clean] *********************************************************

fatal: [192.168.2.2] => error while evaluating conditional: {% if apt_get_contents.stdout.find("0 upgraded") == -1 %} True {% else %} False {% endif %}

FATAL: all hosts have already failed -- aborting
Merge pull request #4285 from blair/apt-module-register-stdout-stderr

apt: pass child process stdout and stdout to m.fail_json() and m.exit_js...