Revert "Add the keys I used to sign the market version of Superuser."

These are obsolete.

This reverts commit 0f15d18a50d721faa8dee67f763405354025e25a.

Change-Id: I645686c5049f8651e99c95f2b775aaae2cca1f3a
build: Default to dtbToolCM

* The default dtbTool isn't the correct module name for the module that
  actually lives in device/qcom/common/dtbtool

Change-Id: I80b427e3652b99742573bc4d2829e51645a8822b