package/libssh2: security bump to latest git

package/libssh2: security bump to latest git

Bump the version to latest git to fix the following security issues:

CVE-2019-3855
 Possible integer overflow in transport read allows out-of-bounds write
 URL: https://www.libssh2.org/CVE-2019-3855.html
 Patch: https://libssh2.org/1.8.0-CVE/CVE-2019-3855.patch

CVE-2019-3856
 Possible integer overflow in keyboard interactive handling allows
 out-of-bounds write
 URL: https://www.libssh2.org/CVE-2019-3856.html
 Patch: https://libssh2.org/1.8.0-CVE/CVE-2019-3856.patch

CVE-2019-3857
 Possible integer overflow leading to zero-byte allocation and out-of-bounds
 write
 URL: https://www.libssh2.org/CVE-2019-3857.html
 Patch: https://libssh2.org/1.8.0-CVE/CVE-2019-3857.patch

CVE-2019-3858
 Possible zero-byte allocation leading to an out-of-bounds read
 URL: https://www.libssh2.org/CVE-2019-3858.html
 Patch: https://libssh2.org/1.8.0-CVE/CVE-2019-3858.patch

CVE-2019-3859
 Out-of-bounds reads with specially crafted payloads due to unchecked use of
 `_libssh2_packet_require` and `_libssh2_packet_requirev`
 URL: https://www.libssh2.org/CVE-2019-3859.html
 Patch: https://libssh2.org/1.8.0-CVE/CVE-2019-3859.patch

CVE-2019-3860
 Out-of-bounds reads with specially crafted SFTP packets
 URL: https://www.libssh2.org/CVE-2019-3860.html
 Patch: https://libssh2.org/1.8.0-CVE/CVE-2019-3860.patch

CVE-2019-3861
 Out-of-bounds reads with specially crafted SSH packets
 URL: https://www.libssh2.org/CVE-2019-3861.html
 Patch: https://libssh2.org/1.8.0-CVE/CVE-2019-3861.patch

CVE-2019-3862
 Out-of-bounds memory comparison
 URL: https://www.libssh2.org/CVE-2019-3862.html
 Patch: https://libssh2.org/1.8.0-CVE/CVE-2019-3862.patch

CVE-2019-3863
 Integer overflow in user authenicate keyboard interactive allows
 out-of-bounds writes
 URL: https://www.libssh2.org/CVE-2019-3863.html
 Patch: https://libssh2.org/1.8.0-CVE/CVE-2019-3863.txt

Drop 0003-openssl-fix-dereferencing-ambiguity-potentially-caus.patch as that
is now upstream.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>