tfshark: fix compilation.

Note: "compilation", not "operation" - after I got it to compile, it
crashed when I tried to run it on a JPEG file.

tfshark.c

@@ -503,7 +503,7 @@ main(int argc, char *argv[])
      dissectors, and we must do it before we read the preferences, in
      case any dissectors register preferences. */
   if (!epan_init(NULL, NULL, TRUE)) {
-    exit_status = INIT_ERROR;
+    exit_status = INIT_FAILED;
     goto clean_exit;
   }