ssh: sssd_ssh fails completely on p11_child timeout

When p11_child fails or timeout is reached, ssh login fails.
With this patch sssd_ssh proceeds to ssh key and password login.

Resolves:
https://pagure.io/SSSD/sssd/issue/3937

Reviewed-by: Jakub Hrozek <jhrozek@redhat.com>
Reviewed-by: Sumit Bose <sbose@redhat.com>

src/responder/ssh/ssh_reply.c

@@ -281,8 +281,11 @@ void ssh_get_output_keys_done(struct tevent_req *subreq)
     ret = cert_to_ssh_key_recv(subreq, state, &keys, &valid_keys);
     talloc_zfree(subreq);
     if (ret != EOK) {
-        DEBUG(SSSDBG_OP_FAILURE, "cert_to_ssh_key request failed.\n");
-        tevent_req_error(req, ret);
+        DEBUG(SSSDBG_MINOR_FAILURE,
+              "cert_to_ssh_key request failed, ssh keys derived "
+              "from certificates will be skipped.\n");
+        /* Ignore ssh keys from certificates and return what we already have */
+        tevent_req_done(req);
         return;
     }