upstart: Modify initctl's set-env to process a list

:Release Notes:
Extend the functionality of the set-env command of initctl to process
multiple NAME=VALUE settings.

:Detailed Notes:
Each invocation of "initctl set-env --global" was measured to take
roughly 12 ms. When it's necessary to set a large number of global
environment variables, this will end up taking a fair amount of time.
By simply extending the set-env command to process multiple NAME=VALUE
settings, only one invocation of initctl is needed.

Also add comments to the existing patch files.

:Testing Performed:
Confirmed that when multiple values were given to set-env --global,
they were all present in the environment of subsequently spawned
processes.

:QA Notes:

:Issues Addressed:
[GF-38599] Upstart: modify initctl's set-env command to process more
           than one argument
[GF-38994] CCC: upstart=1.8-0webos1

Open-webOS-DCO-1.0-Signed-off-by: Ed Chejlava <ed.chejlava@lge.com>
Change-Id: Id443808f0b8b99eebe9f491d261dc7c2bacef0d5
Reviewed-on: https://g2g.palm.com/3456
Reviewed-by: Herb Kuta <herb.kuta@lge.com>
Tested-by: Herb Kuta <herb.kuta@lge.com>
Reviewed-by: Sangwoo Kang <sangwoo82.kang@lge.com>
Reviewed-by: Build Verification
Reviewed-by: Susan Montooth <susan.montooth@lge.com>
Tested-by: Susan Montooth <susan.montooth@lge.com>