In initLocation, use the local post var reference

No need to grab the post from the Activity again.
Reduce num of hasLocation lookups in initLocation

Combine two different if statements, since they're doing similar things
On initLocation, set the Location instance var

If a post has a location, we should set it to the instance var right
away to avoid losing the location.

https://github.com/wordpress-mobile/WordPress-Android/pull/1468#issuecomment-46451795

h/t maxme