varnishevent - bugfix (determining the i args when an n arg is set)

bin/varnishevent/format.c

@@ -746,6 +746,8 @@ FMT_Init(char *err)
 void
 FMT_Get_i_Arg(char *i_arg)
 {
+    i_arg[0] = '\0';
+    
     for (int i = 0; i < MAX_VSL_TAG; i++) {
         char tag = cformat.tags[i] | bformat.tags[i] | zformat.tags[i];
         if (tag) {

bin/varnishevent/varnishevent.c

@@ -581,6 +581,8 @@ main(int argc, char *argv[])
         LOG_Log0(LOG_INFO, "Reading default varnish instance");
     else
         LOG_Log(LOG_INFO, "Reading varnish instance %s", scratch);
+
+    scratch[0] = '\0';
     FMT_Get_i_Arg(scratch);
     assert(VSL_Arg(vd, 'i', scratch) > 0);
     LOG_Log(LOG_INFO, "Reading SHM tags: %s", scratch);