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
Generate extra userdata partition if needed

* To support variants of devices which may come in 16/32/64GB variants.

Change-Id: I74c32d8316f0450a1445fe95a95e5cabb7a9dd1b
build: Default to python2

On some systems, /usr/bin/env python is default to python3, specifiy
python2 to fix that

Change-Id: Ieecb98d69b0e9e958042622b97826d1ba6ef672c
build: Improve roomservice

roomservice has improved in the sense that once a duplicate path is
found, a <remove-project> tag will be added into roomservice.xml

Change-Id: If3e1dc672d25996a0cd19628ece24c010e213adf
Remove webviewchromium from bootclasspath

Will prevent spamming of this message for legacy devices:
Unable to stat classpath element '/system/framework/webviewchromium.jar'

Change-Id: I11d5b9ed6d4aea0646729ed8e87243ccbb13ea57