epicmtd: updater.sh: Revise check for larger system partition (again)

Change-Id: I49d56f4d2646ed1a708afb65544a9103ce6eaa58
epicmtd: Cleanup updater.sh

Various fixes to be more inline with aries-common.

Change-Id: I63ba045c4bc759cfdf0b6e25f6c5a36171c7ddb2
Merge "epicmtd: updater.sh: Revise check for larger system partition (again)" into cm-11.0
Merge "epicmtd: Cleanup updater.sh" into cm-11.0