Squashed adb fixes.

fix up adb to prefer /sbin/sh if it exists

allow always insecure

Change-Id: I5c15731c95d123488e90aaeac5b497f556b53363

Conflicts:

	adb/Android.mk
Merge branch 'master' of https://android.googlesource.com/platform/system/core
Merge branch 'master' of github.com:razrqcom-dev-team/platform_system_core into master-tk