strongswan: handle chacha20poly1305 as AEAD

chacha20policy1305 is also an AEAD cipher, and hence does not
permit a hash algorithm.

Fixes issue #15397.

Signed-off-by: Philip Prindeville <philipp@redfish-solutions.com>

net/strongswan/files/swanctl.init

@@ -141,6 +141,8 @@ is_aead() {
 	case "$cipher" in
 	aes*gcm*|aes*ccm*|aes*gmac*)
 		return 0 ;;
+	chacha20poly1305)
+		return 0 ;;
 	esac
 
 	return 1