mcf: Fix setting SSTATE_MIRRORS variable (v4.0.14)

:Release Notes:
getopts function wasn't setting global SSTATE_MIRRORS variable causing
@sstatemirror_assignment@ replacement to be always empty.

:Detailed Notes:
Move SSTATE_MIRRORS setting into separate function. Move all global
variables together.

:Testing Performed:
Only build tested.

:QA Notes:
No change to image.

:Issues Addressed:

Open-webOS-DCO-1.0-Signed-off-by: Martin Jansa <martin.jansa@lge.com>
Change-Id: I3f96e191993b79c65716b38bdf8fbd4862ff8e9f
Reviewed-on: https://g2g.palm.com/6206
Reviewed-by: DCO Verification
Build: Martin Jansa <Martin.Jansa@lge.com>
Reviewed-by: Martin Jansa <Martin.Jansa@lge.com>
Tested-by: Martin Jansa <Martin.Jansa@lge.com>
Reviewed-by: Build Verification
Reviewed-by: Herb Kuta <herb.kuta@lge.com>
Reviewed-by: Susan Montooth <susan.montooth@lge.com>
mcf: Drop deprecated private mirror option (v4.0.15)

:Release Notes:
It was changing the shared state signatures, so it was disabled and
ignored for long time. Remove all traces of it.

:Detailed Notes:

:Testing Performed:
Only build tested.

:QA Notes:
No change to image.

:Issues Addressed:
[ES-474] Drop the --enable-private-internal-component-mirror/
         --disable-private-internal-component-mirror options to mcf

Open-webOS-DCO-1.0-Signed-off-by: Martin Jansa <martin.jansa@lge.com>
Change-Id: I02f0dc52aa090f4fc75551514f88a8af4e315c54
Reviewed-on: https://g2g.palm.com/6207
Reviewed-by: DCO Verification
Build: Martin Jansa <Martin.Jansa@lge.com>
Reviewed-by: Martin Jansa <Martin.Jansa@lge.com>
Tested-by: Martin Jansa <Martin.Jansa@lge.com>
Reviewed-by: Build Verification
Reviewed-by: Herb Kuta <herb.kuta@lge.com>
Reviewed-by: Susan Montooth <susan.montooth@lge.com>