Verification builds:
1.1.3.1 Retail

Summary:
Ghast fireballs should disappear if the ghast that fired it dies. This is what happens in the Java edition, and used to happen in MCPE, but it has changed in a recent update.

Steps to Reproduce:

1. Kill a ghast that has shot a fireball at you

Observed Results:
The ghast dies, and the fireball continues on it's path until it hits something.

Expected Results:
Usually the fireball would disappear when the ghast dies.

Screenshots/Videos attached: No

Notes:
Wiki Reference:

If a ghast is killed, any fireball launched by that ghast will disappear.