Fix read with date_range where start but no end

[scoriiu]

[bmoscon]

@scoriiu if you want to get this merged in, you'll need to add a test case that illustrates the issue and then is fixed with your fix. You can add one in arctic/tests/integration/tickstore/

[shashank88]

@scoriiu can you add the test as @bmoscon mentioned?

[scoriiu]

Hi guys, will try adding a test these days. Very buys with other projects :(