fix warning: 'cipher_hd' may be used uninitialized in this function

I don't think it's an actual issue, but the new compiler on the mac buildbots
isn't smart enough to tell that.

Change-Id: I759e1afe9c4011d5612be0d15282076be6f5a331
Reviewed-on: https://code.wireshark.org/review/3355
Reviewed-by: Evan Huus <eapache@gmail.com>

epan/dissectors/packet-ipsec.c

@@ -914,6 +914,9 @@ get_esp_sa(gint protocol_typ, gchar *src,  gchar *dst,  gint spi,
 
   g_snprintf(spi_string, IPSEC_SPI_LEN_MAX,"0x%08x", spi);
 
+  *cipher_hd = NULL;
+  *cipher_hd_created = NULL;
+
   /* Check each known SA in turn */
   for (i = 0, j=0; (found == FALSE) && ((i < num_sa_uat) || (j < extra_esp_sa_records.num_records)); )
   {