Added start blocke on no database connection available

lib/DB/ContactDAO.py

@@ -7,18 +7,22 @@ class ContactDAO:
     def __init__(self):
         #print(f"*** File: {__file__}, __init__()")
         self.__con = DbManager().getConnection()
-        self.__cur = self.__con.cursor()
+        if self.__con:
+            self.__cur = self.__con.cursor()
 
     def getContacts(self):
         print(f"*** File: {__file__}, getContacts()")
 
     def addContact(self, contact, enc_key):
         try:
-            self.__cur.callproc("addContactPerson", (enc_key, json.dumps(contact),))
-            self.__con.commit()
-            self.__cur.callproc("getLastInsertId")
-            contact_id = self.__cur.fetchone()
-            return contact_id[0]
+            if self.__cur:
+                self.__cur.callproc("addContactPerson", (enc_key, json.dumps(contact),))
+                self.__con.commit()
+                self.__cur.callproc("getLastInsertId")
+                contact_id = self.__cur.fetchone()
+                return contact_id[0]
+            else:
+                return None
         except mariadb.Error as e:
             print("MDB: " + str(e))
         except Exception as e: