Fix for problem with nr1,nr2,nr3 when ecutrho is 4*ecutwfc
Ensure that if nr1,nr2,nr3 are specified and nr1s,nr2s,nr3s are not and ecutho=4*ecutwfc than the smooth and dense grid have the same dimensions. I think the previous condition was not working as expected.
Note that the OLD condition is FALSE when ecutrho=4*ecutwfc => ecutrho<(4+eps)ecutwfc, On the other hand, the NEW condition is TRUE when ecutrho=4ecutwfc. Also, the new condition looks more understandable to me.