BUG/MEDIUM: mux-fcgi: Return from detach if server don't keep the connection

When the last stream is detached from a FCGI connection, if the server don't add
the connection in its idle list, the connection is destroyed. Thus it is
important to exist immediately from the detach function. A return statement is
missing here.

This bug was introduced in the commit 2444aa5b6 ("MEDIUM: sessions: Don't be
responsible for connections anymore.").

It is a 2.2-dev bug. No need to backport.
1 file changed