logcat: logcatd: make logcatd killable

Near last resort kill logcatd, set /proc/self/oom_score_adj to -600.

Can kill to keep system_server, telephony and bluetooth.

Test: manual, start logpersist, runs
Bug: 62147352
Change-Id: I3723761bf1d2b79ce6a9557d2e78f91cc5497e96
diff --git a/logcat/logcatd.rc b/logcat/logcatd.rc
index 06cc90d..07040b0 100644
--- a/logcat/logcatd.rc
+++ b/logcat/logcatd.rc
@@ -61,3 +61,4 @@
     user logd
     group log
     writepid /dev/cpuset/system-background/tasks
+    oom_score_adjust -600