envsetup: use $(CURDIR) for getting current directory

Change-Id: I5f00faf64ec31d86dd2e48ec038748ce8499380b
Some CM stuff
Run e2fsck on built sparse images.

Bug: 7591683
Change-Id: Id1cba79f7840aab1f0327cb741eda655b45d1b46
build: get rid of the sparse expand stuff

* i don't see a reason why we are doing this because we never deal
with flashing system img rawly
* This will put useless write on ssd..
* we don't have space on ssd

Change-Id: Icd53d161b8515f5eca238b98ad68515d69caa34f