Remove a Linux specific comment from the httping man page.

This change will not be sent upstream.

--- httping-2.4/httping.1.orig 2015-02-16 08:15:41.545818708 -0800

+++ httping-2.4/httping.1 2015-02-16 08:16:09.286228137 -0800

@@ -49,7 +49,7 @@

Retrieve proxy settings from environment variables ('http_proxy' and 'https_proxy').

.TP

.B "\-F"

-Attempt TCP Fast Open while trying to connect to a server (for Linux, version 3.7 onwards of the kernel)

+Attempt TCP Fast Open while trying to connect to a server.

.TP

.B "\-f"

Flood ping: do not sit idle between each ping but ping as fast as the computer and network allow you to.