Keep multiple kernel logs

Currently we are keeping one copy of the kernel log (LAST_KMSG_FILE).
This CL changes to keep up to KEEP_LOG_COUNT copies for kernel logs.

Bug: http://b/18092237
Change-Id: Ied862b5b70cbbae7775f59c78c32ec62aeeca655
(cherry picked from commit bef39710ff50cedf6a4de8eb6c7802f66930aab4)
1 file changed