legacy: Remove privatekey_from_base64().

This function has been introduced for libssh 0.6. So we can remove it
completely.

include/libssh/keyfiles.h

@@ -30,7 +30,4 @@ ssh_string try_publickey_from_file(ssh_session session,
     struct ssh_keys_struct keytab,
     char **privkeyfile, int *type);
 
-ssh_private_key privatekey_from_base64(ssh_session session, const char *b64_pkey,
-    int type, const char *passphrase);
-
 #endif /* KEYFILES_H_ */

include/libssh/libssh.h

@@ -547,9 +547,6 @@ LIBSSH_API int ssh_event_remove_fd(ssh_event event, socket_t fd);
 LIBSSH_API int ssh_event_remove_session(ssh_event event, ssh_session session);
 LIBSSH_API void ssh_event_free(ssh_event event);
 
-LIBSSH_API ssh_private_key privatekey_from_base64(ssh_session session, const char *b64_pkey,
-    int type, const char *passphrase);
-
 #ifndef LIBSSH_LEGACY_0_4
 #include "libssh/legacy.h"
 #endif

src/legacy.c

@@ -343,40 +343,6 @@ char *string_to_char(ssh_string str){
   return ssh_string_to_char(str);
 }
 
-ssh_private_key privatekey_from_base64(ssh_session session,
-                                       const char *b64_pkey,
-                                       int type,
-                                       const char *passphrase) {
-    ssh_auth_callback auth_fn = NULL;
-    void *auth_data = NULL;
-    ssh_private_key privkey;
-    ssh_key key;
-
-    (void) type; /* unused */
-
-    if (session->common.callbacks) {
-        auth_fn = session->common.callbacks->auth_function;
-        auth_data = session->common.callbacks->userdata;
-    }
-
-    key = pki_private_key_from_base64(b64_pkey, passphrase, auth_fn, auth_data);
-    if (key == NULL) {
-        return NULL;
-    }
-
-    privkey = malloc(sizeof(struct ssh_private_key_struct));
-    if (privkey == NULL) {
-        ssh_key_free(key);
-        return NULL;
-    }
-
-    privkey->type = key->type;
-    privkey->dsa_priv = key->dsa;
-    privkey->rsa_priv = key->rsa;
-
-    return privkey;
-}
-
 ssh_private_key privatekey_from_file(ssh_session session,
                                      const char *filename,
                                      int type,