libnmc: Remove verbose logging

Don't log the failure to spawn the auth dialog. This is polluting the
terminal when using nmcli when activating an OpenVPN profile if
/usr/libexec/nm-openvpn-auth-dialog is not available. Since nmcli can
still ask for the credentials, the missing auth dialog does not block
the activation, so the "warning" level is too much. Since it is a
library, any output to the terminal is bad, therefore remove the
logging.

Signed-off-by: Till Maas <opensource@till.name>

src/libnmc-base/nm-secret-agent-simple.c

@@ -795,7 +795,6 @@ try_spawn_vpn_auth_helper(RequestData *request, GPtrArray *secrets)
                                   &auth_dialog_out_fd,
                                   NULL,
                                   &error)) {
-        g_warning("Failed to spawn the auth dialog%s\n", error->message);
         return FALSE;
     }