Catch configuration file parsing errors

Fix #176

gns3server/config.py

@@ -135,7 +135,11 @@ class Config(object):
         Read the configuration files.
         """
 
-        parsed_files = self._config.read(self._files, encoding="utf-8")
+        try:
+            parsed_files = self._config.read(self._files, encoding="utf-8")
+        except configparser.Error as e:
+            log.error("Can't parse configuration file: %s", str(e))
+            return
         if not parsed_files:
             log.warning("No configuration file could be found or read")
         else: