Update libssh2 to 1.8.0

tiennou · tiennou · commit 17112f5321d9 · 2018-02-15T15:38:31.000+01:00
diff --git a/External/libssh2 b/External/libssh2
@@ -1 +1 @@
-Subproject commit f1cfa55b6064ba18fc0005713ed790da579361b5
+Subproject commit 30e9c1347e3b8baa2951db612f05e6d87fc8e2f2
