add tryexec, libmarble needs the .desktop file but marble may not be installed
add tryexec, libmarble needs the .desktop file but marble may not be installed

svn path=/trunk/KDE/kdeedu/marble/; revision=1052072

utkuaydin/marble,David-Gil/marble-dev,oberluz/marble,oberluz/marble,quannt24/marble,AndreiDuma/marble,quannt24/marble,rku/marble,tucnak/marble,probonopd/marble,rku/marble,adraghici/marble,adraghici/marble,David-Gil/marble-dev,Earthwings/marble,utkuaydin/marble,oberluz/marble,tzapzoor/marble,AndreiDuma/marble,adraghici/marble,probonopd/marble,utkuaydin/marble,AndreiDuma/marble,utkuaydin/marble,David-Gil/marble-dev,probonopd/marble,quannt24/marble,utkuaydin/marble,Earthwings/marble,tzapzoor/marble,adraghici/marble,tzapzoor/marble,David-Gil/marble-dev,rku/marble,tzapzoor/marble,probonopd/marble,Earthwings/marble,Earthwings/marble,quannt24/marble,tucnak/marble,rku/marble,adraghici/marble,David-Gil/marble-dev,probonopd/marble,Earthwings/marble,tucnak/marble,utkuaydin/marble,tzapzoor/marble,oberluz/marble,oberluz/marble,tucnak/marble,rku/marble,AndreiDuma/marble,AndreiDuma/marble,tucnak/marble,probonopd/marble,probonopd/marble,tzapzoor/marble,David-Gil/marble-dev,Earthwings/marble,quannt24/marble,AndreiDuma/marble,tzapzoor/marble,tzapzoor/marble,quannt24/marble,tucnak/marble,tucnak/marble,oberluz/marble,rku/marble,adraghici/marble,quannt24/marble