Correct default value of "Allow Duplicate Jobs"

Since bacula commit f91db64cb5dd84e91c3b077e19bfb6f803795f1e the
default of "Allow Duplicate Jobs" has been yes instead of no as the
manual states.

Fixes #241: Correct default value of "Allow Duplicate Jobs"

Signed-off-by: Marco van Wieringen <marco.van.wieringen@bareos.com>

manuals/en/main/dirdconf.tex

@@ -1776,7 +1776,7 @@ \section{Job Resource}
 runs longer than expected because no tapes are available.
 
 If this directive is enabled duplicate jobs will be run.  If
-the directive is set to {\bf no} (default) then only one job of a given name
+the directive is set to {\bf no} then only one job of a given name
 may run at one time, and the action that Bareos takes to ensure only
 one job runs is determined by the other directives (see below).
 
@@ -1785,6 +1785,8 @@ \section{Job Resource}
 cancelling a job, then the current job (the second one started)
 will be cancelled.
 
+The default is {\bf yes}.
+
 % \item [Allow Higher Duplicates = {\textless}yes{\textbar}no{\textgreater}] \hfill \\
 % \index[general]{Allow Higher Duplicates}
 % This directive was implemented in version 5.0.0, but does not work