libssh2: pull in additional commits from meta-oe
b24ef04ae libssh2: Fix build with autoconf 2.70+
d7aa71734 libssh2: enhance ptest
b3e9b51c9 libssh2: fix ptest
f5df715e2 libssh2: enable ptest
c1d1697c5 libssh2: add nativesdk support
3a6cbf246 libssh2: Security Advisory - libssh2 - CVE-2019-17498
40ea4c939 libssh2: upgrade 1.8.2 -> 1.9.0
5a7e65cbf libssh2: Clarify BSD license variant
Signed-off-by: Randy MacLeod <Randy.MacLeod@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>