Fix the crashing of the application when Goole Play Services need to be updated

[nikolay-radkov]

Fix the crashing of the application when a user presses on the map and the Google Play Services need to be updated or at the moment of the process of updating.

E/AndroidRuntime( 5908): java.lang.NullPointerException: Attempt to invoke virtual method 'com.google.android.gms.maps.Projection com.google.android.gms.maps.GoogleMap.getProjection()' on a null object reference
E/AndroidRuntime( 5908): 	at com.airbnb.android.react.maps.AirMapView$13.run(AirMapView.java:643)
E/AndroidRuntime( 5908): 	at android.os.Handler.handleCallback(Handler.java:739)
E/AndroidRuntime( 5908): 	at android.os.Handler.dispatchMessage(Handler.java:95)
E/AndroidRuntime( 5908): 	at android.os.Looper.loop(Looper.java:135)
E/AndroidRuntime( 5908): 	at android.app.ActivityThread.main(ActivityThread.java:5264)
E/AndroidRuntime( 5908): 	at java.lang.reflect.Method.invoke(Native Method)
E/AndroidRuntime( 5908): 	at java.lang.reflect.Method.invoke(Method.java:372)
E/AndroidRuntime( 5908): 	at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:900)
E/AndroidRuntime( 5908): 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:695)

[mattshen]

This PR is supposed to fix #618

I made a PR to fix the issue as well. #1443

Both PRs should have the same effect.

I think a lot of stuff shouldn't be started if map instance is null. However, I didn't find a perfect point to check nullability of map.