logd: LogStatistics leak

- uid = -1 in subtract operation to match add

(cherry pick from commit f48ea7c8dc)

Bug: 15986335
Change-Id: I7d0b85b5334c5264fd04309cb78e0c9aec0ad261

logd/LogStatistics.cpp

@@ -302,6 +302,10 @@ void LidStatistics::add(unsigned short size, uid_t uid, pid_t pid) {
 }
 
 void LidStatistics::subtract(unsigned short size, uid_t uid, pid_t pid) {
+    if (uid == (uid_t) -1) { // init
+        uid = (uid_t) AID_ROOT;
+    }
+
     UidStatisticsCollection::iterator it;
     for (it = begin(); it != end(); ++it) {
         UidStatistics *u = *it;