Use cm's prebuilt ccache, which is a higher version than most distro's ccache package.

Squashed commit of the following:

commit 7b8704691aedeef3f826febf6a4728f0f388d114
Author: nuclearmistake <nuclearmistake@gmail.com>
Date:   Mon Feb 10 21:34:37 2014 -0500

    Revert "Use /usr/bin/ccache if it exists"

    This reverts commit 833d58d7a7a78da6bb7d32d5a2af02046a43ee05.

commit 302fcf626544a5c7dd0bdaec2531df0c4e2c7e69
Author: nuclearmistake <nuclearmistake@gmail.com>
Date:   Mon Feb 10 21:33:46 2014 -0500

    Revert "build: use the system's ccache by default"

    This reverts commit e802113de5ca54b926c6a7a32b231d10e3a0807a.

Change-Id: Ic13f1d0ba5091e5233de6dfbce3a1a40b0cd2694