Remove vmdb_database attributes from VmdbDatabaseConnection

You can't assign to a virtual column and all the other methods
caused errors

app/models/vmdb_database_connection.rb

@@ -17,9 +17,7 @@ class VmdbDatabaseConnection < ApplicationRecord
   virtual_column :task_state,        :type => :string
   virtual_column :wait_resource,     :type => :integer  # oid
   virtual_column :wait_time,         :type => :integer
-  virtual_column :vmdb_database_id,  :type => :integer
 
-  virtual_belongs_to :vmdb_database
   virtual_belongs_to :zone
   virtual_belongs_to :miq_server
   virtual_belongs_to :miq_worker
@@ -49,10 +47,6 @@ def self.log_statistics(output = $log)
     end
   end
 
-  def vmdb_database_id
-    @vmdb_database_id ||= self.class.vmdb_database.id
-  end
-
   def address
     client_addr
   end
@@ -111,14 +105,6 @@ def to_csv_hash
     }
   end
 
-  def vmdb_database
-    VmdbDatabase.find_by(:id => vmdb_database_id)
-  end
-
-  def vmdb_database=(db)
-    self.vmdb_database_id = db.id
-  end
-
   def miq_worker
     @miq_worker ||= MiqWorker.find_current_in_my_region.find_by(:sql_spid => spid)
   end