trunks: Unify logging location

This CL defaults trunks daemon logging to syslog.
Logs can be forwarded to stderr by passing the --log_to_stderr switch.
trunks_client now logs to stderr by default.

Bug: 25567627
TEST=compile and run on DUT

Change-Id: I072a4c1dab9425f997faa0f68e8eae99f1b383fb

trunks_client.cc

diff --git a/trunks_client.cc b/trunks_client.cc
index 2202107..4975470 100644
--- a/trunks_client.cc
+++ b/trunks_client.cc
@@ -135,7 +135,7 @@
 
 int main(int argc, char **argv) {
   base::CommandLine::Init(argc, argv);
-  brillo::InitLog(brillo::kLogToSyslog | brillo::kLogToStderr);
+  brillo::InitLog(brillo::kLogToStderr);
   base::CommandLine *cl = base::CommandLine::ForCurrentProcess();
   if (cl->HasSwitch("help")) {
     puts("Trunks Client: A command line tool to access the TPM.");

trunksd.cc

diff --git a/trunksd.cc b/trunksd.cc
index 4c7b05f..ecb047a 100644
--- a/trunksd.cc
+++ b/trunksd.cc
@@ -112,8 +112,12 @@
 
 int main(int argc, char **argv) {
   base::CommandLine::Init(argc, argv);
-  brillo::InitLog(brillo::kLogToSyslog | brillo::kLogToStderr);
   base::CommandLine *cl = base::CommandLine::ForCurrentProcess();
+  int flags = brillo::kLogToSyslog;
+  if (cl->HasSwitch("log_to_stderr")) {
+    flags |= brillo::kLogToStderr;
+  }
+  brillo::InitLog(flags);
   trunks::CommandTransceiver *transceiver;
   if (cl->HasSwitch("ftdi")) {
     transceiver = new trunks::TrunksFtdiSpi();