libcap, cdrkit, dvdrw-tools, fastd, squid: remove headers >= 3.0 dependency

libcap, cdrkit, dvdrw-tools, fastd, squid: remove headers >= 3.0 dependency

Now that the libcap package has a patch that makes it build with
kernel headers < 3.0 (which was needed for the host variant of
libcap), there is no longer a need to have a dependency on headers >=
3.0 for the target variant of libcap.

All reverse dependencies of libcap are handled in this commit, except
lxc, which will be handled in a separate commit since it needs some
special solution.

The build of all those packages has been tested with a toolchain that
uses kernel headers 2.6.32, which is the oldest that our default glibc
version accepts to use.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>