libssh2: security bump to version 1.7.0

Fixes:
CVE-2016-0787 - diffie_hellman_sha256: convert bytes to bits.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/libssh2/libssh2.hash

@@ -1,2 +1,2 @@
 # Locally calculated after checking pgp signature
-sha256	5a202943a34a1d82a1c31f74094f2453c207bf9936093867f41414968c8e8215	libssh2-1.6.0.tar.gz
+sha256	e4561fd43a50539a8c2ceb37841691baf03ecb7daf043766da1b112e4280d584	libssh2-1.7.0.tar.gz

package/libssh2/libssh2.mk

@@ -4,7 +4,7 @@
 #
 ################################################################################
 
-LIBSSH2_VERSION = 1.6.0
+LIBSSH2_VERSION = 1.7.0
 LIBSSH2_SITE = http://www.libssh2.org/download
 LIBSSH2_LICENSE = BSD
 LIBSSH2_LICENSE_FILES = COPYING