mediawiki - security update

It was discovered that MediaWiki, a wiki engine, did not sufficiently
filter CSS in uploaded SVG files, allowing for cross site scripting.

For the stable distribution (wheezy), this problem has been fixed in
version 1:1.19.19+dfsg-0+deb7u1.

For the unstable distribution (sid), this problem has been fixed in
version 1:1.19.19+dfsg-1.

We recommend that you upgrade your mediawiki packages.