[wsgi] add message about the active interface
Similarly to what done in "stdlib".
msgid ""
msgstr ""
"MIME-Version: 1.0\n"
"Content-Type: text/plain; charset=UTF-8\n"
"Content-Transfer-Encoding: 8bit\n"
"Generated-By: pygettext.py 1.5\n"
"Plural-Forms: nplurals=2; plural=(n > 1);\n"
"PO-Revision-Date: YEAR-MO-DA HO:MI +ZONE\n"