fix issue at vim_db

Change-Id: I05817f1690cd78d8138c31303d97671355965d73
Signed-off-by: tierno <alfonso.tiernosepulveda@telefonica.com>
diff --git a/osm_openvim/vim_db.py b/osm_openvim/vim_db.py
index a2f1f1f..5359c01 100644
--- a/osm_openvim/vim_db.py
+++ b/osm_openvim/vim_db.py
@@ -79,7 +79,7 @@
         Following calls can skip this parameters
         """
         try:
-            with self.lock, self.con:
+            with self.lock:
                 if host:
                     self.host = host
                     self.con = None