This value is read from the ro.boot.bootreason system property.
Bug: 21724738
Change-Id: I43bef3d85ba9c8d87669a91da1aa675d9a86e348
(cherry picked from commit a4a1a4ac85)
boot events in the LOCAL_INIT_RC file, bootstat.rc.
This change also creates the /data/misc/bootstat dir during the
filesystem creation block in init.rc.
Bug: 21724738
Change-Id: I2ad6913c0235d5f926c6ef8b3c65d650159c6ed7