Bug 559, changes to make optional intenal database key

Change-Id: I883bb3f874a917d5632b8aa9e937e08d2d7b5507
Signed-off-by: tierno <alfonso.tiernosepulveda@telefonica.com>
diff --git a/osm_common/dbmongo.py b/osm_common/dbmongo.py
index 8140521..0f89c96 100644
--- a/osm_common/dbmongo.py
+++ b/osm_common/dbmongo.py
@@ -77,7 +77,9 @@
         try:
             if "logger_name" in config:
                 self.logger = logging.getLogger(config["logger_name"])
-            self.master_password = config.get("masterpassword")
+            master_key = config.get("commonkey") or config.get("masterpassword")
+            if master_key:
+                self.set_secret_key(master_key)
             self.client = MongoClient(config["host"], config["port"])
             # TODO add as parameters also username=config.get("user"), password=config.get("password"))
             # when all modules are ready