fdo#66145: do not check IsFirstShared() in SwPageDesc::GetLeftFmt()

... and GetRightFmt().  If the first format is requested it must be
returned; the sharing works by copying the SwFmtHeader/Footer from
aMaster to the other members.

(regression from 4dc78aee)

Change-Id: I1708f01c18b155ae75c14fc407e52ccd2bd798d7
(cherry picked from commit 4df438c9)
Reviewed-on: https://gerrit.libreoffice.org/5530Reviewed-by: Petr Mladek <pmladek@suse.cz>
Tested-by: Petr Mladek <pmladek@suse.cz>
Reviewed-by: Thorsten Behrens <tbehrens@suse.com>
Reviewed-by: Miklos Vajna <vmiklos@suse.cz>

sw/source/core/layout/pagedesc.cxx

@@ -348,14 +348,14 @@ sal_Bool SwPageDesc::IsFollowNextPageOfNode( const SwNode& rNd ) const
 SwFrmFmt *SwPageDesc::GetLeftFmt(bool const bFirst)
 {
     return (nsUseOnPage::PD_LEFT & eUse)
-            ? (bFirst && !IsFirstShared()) ? &aFirst : &aLeft
+            ? ((bFirst) ? &aFirst : &aLeft)
             : 0;
 }
 
 SwFrmFmt *SwPageDesc::GetRightFmt(bool const bFirst)
 {
     return (nsUseOnPage::PD_RIGHT & eUse)
-            ? (bFirst && !IsFirstShared()) ? &aFirst : &aMaster
+            ? ((bFirst) ? &aFirst : &aMaster)
             : 0;
 }