logpersist: switch to pgrep from ps

Changes expected output from a line cut from the less than portable
ps output to reporting the pid of logcatd (uid=logd comm=logcat).
Preserve reporting an error code if logcatd did not start.

Bug: 29075536
Change-Id: I61aa0a4787d4594c415d2c7db5bbb0e512676bf8
1 file changed
tree: 2d693c4bed4b911d2d6aa55d61ef90faa0ef7a10
  1. liblog/
  2. logcat/
  3. logd/
  4. logwrapper/