check_http: Document the new -E option

Mention the -E/--extended-perfdata flag in the --help output.

plugins/check_http.c

@@ -1522,6 +1522,8 @@ print_help (void)
   printf ("    %s\n", _("String to be sent in http header as \"User Agent\""));
   printf (" %s\n", "-k, --header=STRING");
   printf ("    %s\n", _("Any other tags to be sent in http header. Use multiple times for additional headers"));
+  printf (" %s\n", "-E, --extended-perfdata");
+  printf ("    %s\n", _("Print additional performance data"));
   printf (" %s\n", "-L, --link");
   printf ("    %s\n", _("Wrap output in HTML link (obsoleted by urlize)"));
   printf (" %s\n", "-f, --onredirect=<ok|warning|critical|follow|sticky|stickyport>");
@@ -1588,7 +1590,7 @@ print_usage (void)
   printf ("%s\n", _("Usage:"));
   printf (" %s -H <vhost> | -I <IP-address> [-u <uri>] [-p <port>]\n",progname);
   printf ("       [-J <client certificate file>] [-K <private key>]\n");
-  printf ("       [-w <warn time>] [-c <critical time>] [-t <timeout>] [-L] [-a auth]\n");
+  printf ("       [-w <warn time>] [-c <critical time>] [-t <timeout>] [-L] [-E] [-a auth]\n");
   printf ("       [-b proxy_auth] [-f <ok|warning|critcal|follow|sticky|stickyport>]\n");
   printf ("       [-e <expect>] [-d string] [-s string] [-l] [-r <regex> | -R <case-insensitive regex>]\n");
   printf ("       [-P string] [-m <min_pg_size>:<max_pg_size>] [-4|-6] [-N] [-M <age>]\n");