ca-certificates: submit sysroot patch upstream, drop default-sysroot.patch

ca-certificates: submit sysroot patch upstream, drop default-sysroot.patch

ca-certificates/0002-update-ca-certificates-use-SYSROOT.patch
was using a non-standard environment variable, and was replaced
with a patch that adds a command line option (and then this
was submitted upstream). ca-certificates recipe was tweaked accordingly,
and nothing else in core or meta-oe is using update-ca-certificates.

Drop default-sysroot.patch as the use case is unclear: sysroot
is explicitly specified in all known invocations of update-ca-certificate,
and if there's a place where it isn't, then update-ca-certificates
will error out trying to write to /etc, and should be fixed to
explicitly specify the sysroot.

Signed-off-by: Alexander Kanavin <alex@linutronix.de>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>