Drop [DEFAULT]root_helper config option

The option is not used anywhere in the codebase. Manila uses "sudo"
together with "rootwrap".

Change-Id: If276a1bac32f5273c433805263d507e2fc3b2f26

doc/source/configuration/tables/manila-share.inc

@@ -56,8 +56,6 @@
      - (Integer) Time to wait for access rules to be allowed/denied on backends when migrating shares using generic approach (seconds).
    * - ``network_config_group`` = ``None``
      - (String) Name of the configuration group in the Manila conf file to look for network config options.If not set, the share backend's config group will be used.If an option is not found within provided group, then'DEFAULT' group will be used for search of option.
-   * - ``root_helper`` = ``sudo``
-     - (String) Deprecated: command to use for running commands as root.
    * - ``share_manager`` = ``manila.share.manager.ShareManager``
      - (String) Full class name for the share manager.
    * - ``share_name_template`` = ``share-%s``

manila/common/config.py

@@ -106,10 +106,6 @@ global_opts = [
                default='month',
                help='Time period to generate share usages for.  '
                     'Time period must be hour, day, month or year.'),
-    cfg.StrOpt('root_helper',
-               default='sudo',
-               help='Deprecated: command to use for running commands as '
-                    'root.'),
     cfg.StrOpt('rootwrap_config',
                help='Path to the rootwrap configuration file to use for '
                     'running commands as root.'),

releasenotes/notes/remove-root-helper-config-option-fd517b0603031afa.yaml

@@ -0,0 +1,7 @@
+---
+other:
+  - |
+    The "root_helper" configuration option from the [DEFAULT] section
+    got removed. This option was not used anywhere in the codebase.
+    Manila uses "sudo" together with "rootwrap" to allow unprivileged users
+    running actions as root.