logcat: document help tail from time

(cherry picked from commit 6bdc95154fcac5d5c2f0752a2a7c8f1d136699c0)

Bug: 17323719
Change-Id: Id057dde60e699c946828f4aeabedf1728b3bc877
1 file changed
tree: 3ed9f584fb393e2ffcdfc357148c13efbd5fc121
  1. liblog/
  2. logcat/
  3. logd/
  4. logwrapper/