bugreportz: don't write last line when it times out.

Bug: 112102388
Bug: 111720061

Test: m -j bugreportz_test && adb push \
  ${OUT}/data/nativetest/bugreportz_test/bugreportz_test /system/bin && \
  adb shell /system/bin/bugreportz_test
Test: m -j bugreportz && adb push ${OUT}/system/bin/bugreportz /system/bin && \
  adb shell setprop dumpstate.dry_run true && adb shell bugreportz -p

Change-Id: Ib4219d39070dc6958f83d4a2be34c212a9b1fe2b
diff --git a/cmds/bugreportz/bugreportz.h b/cmds/bugreportz/bugreportz.h
index 304e4b3..7af289b 100644
--- a/cmds/bugreportz/bugreportz.h
+++ b/cmds/bugreportz/bugreportz.h
@@ -16,6 +16,7 @@
 #define BUGREPORTZ_H
 
 // Calls dumpstate using the given socket and output its result to stdout.
+// Ownership of the socket is not transferred.
 int bugreportz(int s, bool show_progress);
 
 #endif  // BUGREPORTZ_H