adb: Allow configuring the adb shell with a persistent property.

To set to bash: setprop persist.sys.adb.shell /system/xbin/bash

Change-Id: I24e65f4592aaf23356c13db02c9869076df3b841
Add DC-HSPA+ TCP buffer sizes

Change-Id: I5e7ca981ed79a3563215dd7fcef3504c39e973d5

Conflicts:
	rootdir/init.rc
fs_mgr.c: fix i++ error and optimize code

Change-Id: I4d7c9846143ec5b9f76af42c7ee4d5a7c2a3fd6d