How to remove/replace meta http-equiv=“X-UA-Compatible” tag in Diazo

Question

I'm working on theming Plone site using Diazo. Unthemed site is based on Sunburst theme so this tag is inserted by main template to the /html/head:

<meta http-equiv="X-UA-Compatible" content="IE=edge" />

My design contains

<meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7" />

so I need to replace this tag only. I want to preserve other meta tags generated by Plone.

These rules does not work for me:

<drop content="/html/head/meta[@http-equiv='IE=edge']" />
<after theme-children="/html/head">
    <meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7" />
</after>

What rules should I use?