[web] fix language negotiation
Regression caused by commit 6fd0ac6506cb "[web-request] handle default
language earlier". We would handle language negotiation at request
init time, but overwrite the selected language with the site default
when calling set_cnx.
\.svn
^build$
^dist$
\.pyc$
\.pyo$
\.bak$
\.old$
\~$
\#.*?\#$
\.swp$
^doc/book/en/apidoc$
\.old$
syntax: regexp
.*/data/database/.*\.sqlite
.*/data/database/.*\.config
.*/data/database/tmpdb.*
.*/data/ldapdb/.*
^doc/html/
^doc/doctrees/
^doc/book/en/devweb/js_api/
data/pgdb/