sysroot: Make sure ld.co.conf only uses absolute paths

dpkg-shlibdeps doesn’t chdir() to /etc before parsing /etc/ld.so.conf, which it needs to add multiarch paths to the library path list. Not having multiarch files around, it fails to find any dependencies except those in non-multiarch paths.

Signed-off-by: Andrej Shadura andrew.shadura@collabora.co.uk