Bug 1022733 - Entry points lost their splash screen/overlay icons

The origin for applications that have different entry points (e.g.,
Dialer and Contacts are the same application, Communications) also
contains a pathname, so we need to remove that from the origin before
appending the splash icon path.
Merge pull request #20275 from lanker-sony/1022733-splash_icon

Bug 1022733 - Entry points lost their splash screen/overlay icons