cowbuilder: fix sources.list for wheezy-backports
cowbuilder: don't declare a local variable in a loop
cowbuilder: workaround a bug in Lucid libc6

The postinst of Lucid libc6 expect a kernel version X.Y.Z. Use the
uname26 personality to provide that. There is another bug if uname -r
is not X.Y.Z-arch (for example 3.11-trunk-amd64). There is little we
can do from the command-line for this one.
cowbuilder: oldstable is not an Ubuntu release
cowbuilder: split long lines