Subsilver2 captcha_qa template has wrong title

The title bar for the CAPTCHA_QA template in subsilver2 incorrectly uses

{QA_CONFIRM_QUESTION} instead of {L_CONFIRM_QUESTION_EXPLAIN}. This has the effect of causing the CAPTCHA_QA template in subsilver2 to display the question twice: once in the title bar and once in the CAPTCHA area.

This is a very minor bug and can be fixed by simply opening up styles/subsilver2/template/captcha_qa.html and replacing line 2:
<th colspan="2" valign="middle">{QA_CONFIRM_QUESTION}

</th>
with:
<th colspan="2" valign="middle">

{L_CONFIRM_QUESTION_EXPLAIN}

</th>