sc: Stop pushing an extra error

as MustHaveParamCount() already does it when returning false.

Change-Id: Ia4f8998a2f65eea5e6be3fd21b5ca724d13770d0
Reviewed-on: https://gerrit.libreoffice.org/55265Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Markus Mohrhard <markus.mohrhard@googlemail.com>

sc/source/core/tool/interpr7.cxx

@@ -429,10 +429,7 @@ void ScInterpreter::ScDebugVar()
     }
 
     if (!MustHaveParamCount(GetByte(), 1))
-    {
-        PushIllegalParameter();
         return;
-    }
 
     rtl_uString* p = GetString().getDataIgnoreCase();
     if (!p)