add tuning enable variable

Add a variable that when set, enables tuning logging.  This variable is
set to false.

Tuning can be enabled via "-t" "--tuning" on the command line.
With a parameter is the path where to write the logging information.

Change-Id: I6eb8035d56cc3301face21e9375c02fc9fcc5b31
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/pid/zone.hpp b/pid/zone.hpp
index 94082e9..a458011 100644
--- a/pid/zone.hpp
+++ b/pid/zone.hpp
@@ -5,6 +5,7 @@
 #include "pidcontroller.hpp"
 #include "sensors/manager.hpp"
 #include "sensors/sensor.hpp"
+#include "tuning.hpp"
 
 #include <fstream>
 #include <map>
@@ -51,9 +52,10 @@
         _minThermalOutputSetPt(minThermalOutput),
         _failSafePercent(failSafePercent), _mgr(mgr)
     {
-#ifdef __TUNING_LOGGING__
-        _log.open("/tmp/swampd.log");
-#endif
+        if (tuningLoggingEnabled && !tuningLoggingPath.empty())
+        {
+            _log.open(tuningLoggingPath);
+        }
     }
 
     double getMaxRPMRequest(void) const override;
@@ -87,10 +89,8 @@
     void addFanInput(const std::string& fan);
     void addThermalInput(const std::string& therm);
 
-#ifdef __TUNING_LOGGING__
     void initializeLog(void);
     std::ofstream& getLogHandle(void);
-#endif
 
     /* Method for setting the manual mode over dbus */
     bool manual(bool value) override;
@@ -98,9 +98,7 @@
     bool failSafe() const override;
 
   private:
-#ifdef __TUNING_LOGGING__
     std::ofstream _log;
-#endif
 
     const int64_t _zoneId;
     double _maximumRPMSetPt = 0;