man/npcd.8: Do not use hyphens as minus sign.

I.e., escape '-' characters which are interpreted as hyphens by groff. This
allows to copy&paste command-line options from the manpage even when using
UTF-8 (and possibly other) locales.

man/npcd.8.in

@@ -7,7 +7,7 @@
 .SH NAME
 npcd \- Nagios Performance C Daemon
 .SH SYNOPSIS
-\fBnpcd\fR [ \fB-d | --daemon\fR ] ( \fB-f | --config\fR ) \fI<configfile>
+\fBnpcd\fR [ \fB\-d | \--daemon\fR ] ( \fB\-f | \--config\fR ) \fI<configfile>
 .SH DESCRIPTION
 The \fBnpcd\fR is a daemon processing nagios performance data.
 .PP