Fix lintian warning in manpage.

Author: Chris Taylor <ctaylor@debian.org>
--- a/doc/pgdbf.man
+++ b/doc/pgdbf.man
@@ -4,7 +4,7 @@ pgdbf \- convert XBase / FoxPro tables t
 
 .SH SYNOPSIS
 .B pgdbf
-[\-cCdDeEhqQtTuU] [-m memofile] filename [indexcolumn ...]
+[\-cCdDeEhqQtTuU] [\-m memofile] filename [indexcolumn ...]
 
 .SH DESCRIPTION
 PgDBF is a program for converting XBase databases - particularly FoxPro
