OGRLineString::setNumPoints() : add an optional argument to avoid zeroizing the arrays

git-svn-id: https://svn.osgeo.org/gdal/trunk/gdal@26628 f0d54148-0727-0410-94bb-9a71ac55c965
Spatialite: optimize geometry reading by using OGRLineString::setNumPoints() with no zeroizing option

git-svn-id: https://svn.osgeo.org/gdal/trunk/gdal@26629 f0d54148-0727-0410-94bb-9a71ac55c965