Share with group tab not shown if Member lock is enabled

https://gitlab.zendesk.com/agent/tickets/82095

Summary

When Member lock is enabled to prevent adding new members to project membership within a group the Share with group tab is also not available.

Steps to reproduce

1. Go to ../groups/<group-name>/edit
2. Enable Member lock and leave Share with group lock option unchecked
3. Go to ../<group-name>/<project-name>/project_members
4. Observe neither Add member or Share with group tabs are available

Example Project

https://gitlab.com/dummy-projects/rails-template/project_members

What is the current bug behavior?

When you enable Member lock it also prevents you from sharing a project with other groups.

What is the expected correct behavior?

When Member lock is enabled (and Share with group lock is disabled) the Share with group tab should still be shown.

Possible fixes

https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/11951/diffs