Remove man page for xrdp-xcon, as xrdp-xcon not installed

Tools that are not installed can be documented by text files in other
formats. There is nothing useful in the xrdp-xcon manual page that would
need to be preserved.

docs/man/xrdp-xcon.8

@@ -1,14 +0,0 @@
-.TH "xrdp-xcon" "8" "0.9.1" "xrdp team"
-.SH NAME
-xrdp\-xcon \- X11 event loop debugging helper for XRDP
-
-.SH SYNOPSIS
-.B xrdp\-xcon
-
-.SH DESCRIPTION
-.PP
-\fBxrdp\-xcon\fP is a X application, which just opens a connection to the X server and polls for events.
-It's pretty useless.
-
-.SH SEE ALSO
-.BR xev (1).