pki: Fix possible segfault in ssh_key_type_from_name().

src/pki.c

@@ -178,6 +178,10 @@ const char *ssh_key_type_to_char(enum ssh_keytypes_e type) {
  * @return              The enum ssh key type.
  */
 enum ssh_keytypes_e ssh_key_type_from_name(const char *name) {
+    if (name == NULL) {
+        return SSH_KEYTYPE_UNKNOWN;
+    }
+
     if (strcmp(name, "rsa1") == 0) {
         return SSH_KEYTYPE_RSA1;
     } else if (strcmp(name, "rsa") == 0) {