dask: deprecate old worker options

Author: alvarolopez

deepaas/config.py

@@ -45,16 +45,26 @@
     cfg.IntOpt('predict-workers',
                short='p',
                default=1,
+               deprecated_for_removal=True,
                help="""
 Specify the number of workers to spawn for prediction tasks. If using a CPU you
 probably want to increase this number, if using a GPU probably you want to
 leave it to 1. (defaults to 1)
+
+This option is deprecated for removal, as DEEPaaS has switched to Dask to
+manage the execution of background tasks. Please check the documentation
+for the 'dask-config' option for more details.
 """),
     cfg.IntOpt('train-workers',
                default=1,
+               deprecated_for_removal=True,
                help="""
 Specify the number of workers to spawn for training tasks. Unless you know what
 you are doing you should leave this number to 1. (defaults to 1)
+
+This option is deprecated for removal, as DEEPaaS has switched to Dask to
+manage the execution of background tasks. Please check the documentation
+for the 'dask-config' option for more details.
 """),
     cfg.StrOpt('dask-config',
                default=None,