With strict compiler settings returning CAAnimation * from indeterminate property fails to compile.

The existing code fails with strict compiler settings. Return 0 if not
indeterminate, 1 if it is.

DACircularProgressView.m:216:12: error: incompatible pointer to integer
conversion returning 'CAAnimation *__strong' from a function with
result type 'NSInteger' (aka 'int');  [-Werror]
return spinAnimation;