"struct libssh2_knownhost" is now part of the internal struct for each known

host so we now only return pointers to structs instead of having the app
allocate a full struct

I moved the private struct definition into knownhosts.c instead of exposing it
wider in libssh2_priv.h

I thus modified the proto for two functions that previously used 'struct
libssh2_knownhost *' to receive data.

src/libssh2_priv.h

@@ -940,24 +940,6 @@ struct list_node {
 
 /* --------- */
 
-struct known_host {
-    struct list_node node;
-    char *name;      /* points to the name or the hash (allocated) */
-    size_t name_len; /* needed for hashed data */
-    int typemask;    /* plain, sha1, custom, ... */
-    char *salt;      /* points to binary salt (allocated) */
-    size_t salt_len; /* size of salt */
-    char *key;       /* the (allocated) associated key. This is kept base64
-                        encoded in memory. */
-};
-
-struct _LIBSSH2_KNOWNHOSTS
-{
-    LIBSSH2_SESSION *session;  /* the session this "belongs to" */
-    struct list_head head;
-};
-
-
 /* libssh2 extensible ssh api, ultimately I'd like to allow loading additional
    methods via .so/.dll */