Bug#647241: openssh-client: ssh -f doesn't fork+exit when connection sharing

[Peter Chubb <peter.chubb@nicta.com.au>]

Package: openssh-client
Version: 1:5.9p1-1
Severity: normal

Dear Maintainer,
    I have connection sharing turned ON for all hosts in my configuration.

If I do:
	ssh -X -f somehost xterm
	ssh -X -f somehost xterm
the second ssh doesn't fork and exit, but remains the foreground process.

..ssh/config includes:

Host *
      ControlMaster auto
      ControlPath /tmp/%r@%h:%p

-- System Information:
Debian Release: wheezy/sid
  APT prefers oldstable
  APT policy: (500, 'oldstable'), (500, 'unstable'), (500, 'testing'), (500, 'stable')
Architecture: i386 (i686)

Kernel: Linux 3.1.0-07178-g839d881-dirty (SMP w/2 CPU cores; PREEMPT)
Locale: LANG=en_AU.utf8, LC_CTYPE=en_AU.utf8 (charmap=UTF-8) (ignored: LC_ALL set to en_AU.utf8)
Shell: /bin/sh linked to /bin/bash

Versions of packages openssh-client depends on:
ii  adduser                3.113
ii  debconf [debconf-2.0]  1.5.41
ii  dpkg                   1.16.1.1
ii  libc6                  2.13-21
ii  libedit2               2.11-20080614-3
ii  libgssapi-krb5-2       1.9.1+dfsg-3
ii  libselinux1            2.1.0-1
ii  libssl1.0.0            1.0.0e-2
ii  passwd                 1:4.1.4.2+svn3283-3
ii  zlib1g                 1:1.2.3.4.dfsg-3

Versions of packages openssh-client recommends:
ii  openssh-blacklist        0.4.1
ii  openssh-blacklist-extra  0.4.1
ii  xauth                    1:1.0.6-1

Versions of packages openssh-client suggests:
pn  keychain      <none>
pn  libpam-ssh    <none>
pn  monkeysphere  <none>
pn  ssh-askpass   <none>

-- no debconf information