fdo#60250: InsertNewPage: copy margins for mirrored pages

When there is no explicit first page, set the proper left or right
margins, which are different for mirrored page styles.
(regression from a964cf66)

Change-Id: I56ccc6f7987accefc27d627d2427ee37d83bd758

sw/source/core/layout/frmtool.cxx

@@ -2729,11 +2729,14 @@ SwPageFrm * InsertNewPage( SwPageDesc &rDesc, SwFrm *pUpper,
             {
                 rDesc.GetFirst().SetFmtAttr( rDesc.GetMaster().GetHeader() );
                 rDesc.GetFirst().SetFmtAttr( rDesc.GetMaster().GetFooter() );
+                // fdo#60250 copy margins for mirrored pages
+                rDesc.GetFirst().SetFmtAttr( rDesc.GetMaster().GetLRSpace() );
             }
             else
             {
                 rDesc.GetFirst().SetFmtAttr( rDesc.GetLeft().GetHeader() );
                 rDesc.GetFirst().SetFmtAttr( rDesc.GetLeft().GetFooter() );
+                rDesc.GetFirst().SetFmtAttr( rDesc.GetLeft().GetLRSpace() );
             }
         }
         pFmt = rDesc.GetFirstFmt();