Small fix where a space was added before \n in fast-log if a xref wasn't used

src/alert-fastlog.c

@@ -126,6 +126,7 @@ TmEcode AlertFastLogIPv4(ThreadVars *tv, Packet *p, void *data, PacketQueue *pq)
                 timebuf, pa->gid, pa->sid, pa->rev, pa->msg, pa->class_msg, pa->prio, IPV4_GET_IPPROTO(p), srcip, p->sp, dstip, p->dp);
 
         if(pa->references != NULL)  {
+            fprintf(aft->file_ctx->fp," ");
             for (ref = pa->references; ref != NULL; ref = ref->next)   {
                 fprintf(aft->file_ctx->fp,"[Xref => %s%s]", ref->key, ref->reference);
             }
@@ -167,6 +168,7 @@ TmEcode AlertFastLogIPv6(ThreadVars *tv, Packet *p, void *data, PacketQueue *pq)
                 timebuf, pa->gid, pa->sid, pa->rev, pa->msg, pa->class_msg, pa->prio, IPV6_GET_L4PROTO(p), srcip, p->sp, dstip, p->dp);
 
         if(pa->references != NULL)  {
+            fprintf(aft->file_ctx->fp," ");
             for (ref = pa->references; ref != NULL; ref = ref->next)   {
                 fprintf(aft->file_ctx->fp,"[Xref => %s%s]", ref->key, ref->reference);
             }