Fix a race condition on ReportHandler::mBatch

Hold mLock when accessing mBatch and mHandlerLooper in ReportHandler.

Fixes: 147326028
Test: Take an incident report. Verify no race condition.
Change-Id: I9d6da0067731f253532f60e5abb12dfb238b5411
diff --git a/cmds/incidentd/src/Section.cpp b/cmds/incidentd/src/Section.cpp
index dec9cb0..114cbb8 100644
--- a/cmds/incidentd/src/Section.cpp
+++ b/cmds/incidentd/src/Section.cpp
@@ -755,7 +755,7 @@
         if (stat(link_name, &fileStat) != OK) {
             continue;
         }
-        size_t exe_name_len = readlink(link_name, exe_name, EXE_NAME_LEN);
+        ssize_t exe_name_len = readlink(link_name, exe_name, EXE_NAME_LEN);
         if (exe_name_len < 0 || exe_name_len >= EXE_NAME_LEN) {
             ALOGE("[%s] Can't read '%s': %s", name.string(), link_name, strerror(errno));
             continue;