Target organization should be configurable by slug

[meteozond]

Changing organization name from UI will brake auth functionality configured through the AUTH_LDAP_DEFAULT_SENTRY_ORGANIZATION, it is more suitable to use organization slug for this.

[jinceon]

I meet this problem. it always display no_organization_access when ldap user logged in.

thank you very much. after I change AUTH_LDAP_DEFAULT_SENTRY_ORGANIZATION to my org_name instead of org_slug, problem solved.