openssl10: rename back to openssl and make it the default via PREFERRED_VERSION

openssl10: rename back to openssl and make it the default via PREFERRED_VERSION

openssl 1.1 broke 3rd party layers a lot more than was expected; let's flip
the switch at the start of next development cycle.

Add a PROVIDES = "openssl10" to openssl 1.0 recipe; any dependency that is
not compatible with 1.1 should use that in its DEPENDS, as the 1.0
recipe will later be renamed back to openssl10. This does not always work:
http://lists.openembedded.org/pipermail/openembedded-core/2017-August/140957.html
but for many recipes it does.

Signed-off-by: Alexander Kanavin <alexander.kanavin@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>