CONTRIB: debug: add the show-fd-to-flags script

This script reads the output of a "show fd" command and for each line
showing a connection, will decode its flags by calling "flags".
diff --git a/contrib/debug/show-fd-to-flags.sh b/contrib/debug/show-fd-to-flags.sh
new file mode 100755
index 0000000..29757c3
--- /dev/null
+++ b/contrib/debug/show-fd-to-flags.sh
@@ -0,0 +1,2 @@
+#!/bin/sh
+awk '{print $12}' | grep cflg= | sort | uniq -c | sort -nr | while read a b; do c=${b##*=}; d=$(${0%/*}/flags conn $c);d=${d##*= }; printf "%6d %s    %s\n" $a "$b" "$d";done