PYTHONPATH default to empty string, fix #5

src/sot-talos-controller.cpp

@@ -147,7 +147,7 @@ startupPython()
 {
   std::ofstream aof(LOG_PYTHON.c_str());
   runPython (aof, "import sys, os", *interpreter_);
-  runPython (aof, "pythonpath = os.environ['PYTHONPATH']", *interpreter_);
+  runPython (aof, "pythonpath = os.environ.get('PYTHONPATH', '')", *interpreter_);
   runPython (aof, "path = []", *interpreter_);
   runPython (aof,
 	     "for p in pythonpath.split(':'):\n"
@@ -163,4 +163,3 @@ startupPython()
   dynamicgraph::rosInit (true);
   aof.close();
 }
-