How to protect LM317 from output short?
When using a voltage regulator like this in an elevated voltage configuration the output capacitor charging issue will always present this momentary issue of over stress of the voltage across the regulator. In your particular case the solution to the 45V across the regulator would take extra components and circuit additions that may very well add up to the cost of using the higher voltage rated regulator in the first place. 

If you need to use the lower voltage rated LM317 then you could add a circuit similar to the following. This design keeps the input to output differential of the LM317 to less than the zener voltage.



The above circuit comes from this TI application note which you can access for more information.