Build - 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: I6fdb51ec440503db1395042f1e3c9ab07026ec6b
Signed-off-by: STELIX <ssspinni@gmail.com>
Build - envsetup: add a helper to fix "out/target/common" not being really common

* out/target/common isn't really common, and if you do
back to back builds for multiple devices, that is noticable.
* Use out/target/common-$device instead, and link the appropriate
dir to out/target/common every time lunch() is run, if
CM_FIXUP_COMMON_OUT is set.
* Refer https://groups.google.com/forum/#!topic/android-
building/ispbOgzoyg8
for more info.

Change-Id: I4d841239a9d1b97528a3a2f005c9442228d15c9c
Signed-off-by: STELIX <ssspinni@gmail.com>