service: Support base switches::kV

This is a libbase built-in command-line flag to set log verbosity,
so that the VLOG macro does the right thing. This CL enables that for
the daemon. To enable VLOGs with a given verbosity level and below, do

bluetoothtbd --v=<level>

Change-Id: I128a42c52425c37640c016c3c6158419cc1c0f66
diff --git a/service/main.cpp b/service/main.cpp
index 2f28815..93eb25f 100644
--- a/service/main.cpp
+++ b/service/main.cpp
@@ -38,6 +38,12 @@
   base::AtExitManager exit_manager;
   base::CommandLine::Init(argc, argv);
 
+  logging::LoggingSettings log_settings;
+  if (!logging::InitLogging(log_settings)) {
+    LOG(ERROR) << "Failed to set up logging";
+    return EXIT_FAILURE;
+  }
+
   // TODO(armansito): Initialize base/logging. By default it will dump to stdout
   // but we might want to change that based on a command-line switch. Figure out
   // how to route the logging to Android's syslog. Once that's done, we won't