Remove script/end script whenever possible

:Release Notes:
Upstart scripts using script/end script result in one extra /bin/sh
process hanging around eatinmg a bit of memory and such

: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
TV, in addition to the extra time it took Upstart to spawn those shells
which then spawned the actual binaries.
Having been poked by Sailesh and Jayoon to re-examine, I found that
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: activitmanager 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

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

Change-Id: Ia837338da681dfa071e7ad00c48eff9de0a9856e
Reviewed-on: https://g2g.palm.com/3262
Reviewed-by: Build Verification
Reviewed-by: Sangwoo Kang <sangwoo82.kang@lge.com>
Tested-by: Sangwoo Kang <sangwoo82.kang@lge.com>
Reviewed-by: Ed Chejlava <ed.chejlava@lge.com>