Remove script/end script whenever possible

:Release Notes:
- Modify upstart script to remove a dangling process.
- Modify process start position to improve UI boottime.

:Detailed Notes:
Having required everyone to use script/end script instead of exec, I
inadvertently led to 70+ copies of /bin/sh leftover after booting the
machine, in addition to the extra time it took Upstart to spawn
those shells which then spawned the actual binaries.
Actually, the problems I thought were being caused by 'exec' were
actually caused by 'expect' (which we no longer try to use).
Replacing the 'script' blocks with 'exec' where possible reduced the
number of excess /bin/sh processes to 1.

:Testing Performed:
Based on #292 + this change: smartkey was executed correctly
with this change and there was no /bin/sh stuff.

:QA Notes:

:Issues Addressed:
[GF-35091] Upstart scripts leaving many dangling /bin/sh procs
[GF-35147] [Boottime] Make best boot sequence to support showcase-app
           initialization

Open-webOS-DCO-1.0-Signed-off-by: Sangwoo Kang <sangwoo82.kang@lge.com>

Change-Id: Ie458cc0f8a024afaf486522fe117fc99816cb872
Reviewed-on: https://g2g.palm.com/3325
Reviewed-by: Build Verification
Reviewed-by: Sangwoo Kang <sangwoo82.kang@lge.com>
Tested-by: Sangwoo Kang <sangwoo82.kang@lge.com>
Reviewed-by: Roger Stringer <roger.stringer@lge.com>
Reviewed-by: Ed Chejlava <ed.chejlava@lge.com>