Use yaml.safe_load instead of yaml.load

Change-Id: I9872174f0205568c2b62f1ea7bf2cc20586327be
Signed-off-by: garciadeblas <gerardo.garciadeblas@telefonica.com>
diff --git a/osm_mon/core/config.py b/osm_mon/core/config.py
index 815e66e..1dfb16c 100644
--- a/osm_mon/core/config.py
+++ b/osm_mon/core/config.py
@@ -43,7 +43,7 @@
             path = "mon.yaml"
             config_file = pkg_resources.resource_filename(__name__, path)
         with open(config_file) as f:
-            self.conf = yaml.load(f)
+            self.conf = yaml.safe_load(f)
 
     def get(self, section, field=None):
         if not field: