Re-enabling Organization deletion tests via CLI.

Since most (if not all) Bugzilla issues related to org deletion are now
closed or ready for testing, it is safe to re-enable the CLI tests that
we had disabled before.

The Bugzilla issues are:

* https://bugzilla.redhat.com/show_bug.cgi?id=1061658
* https://bugzilla.redhat.com/show_bug.cgi?id=1076568
* https://bugzilla.redhat.com/show_bug.cgi?id=1096241
* https://bugzilla.redhat.com/show_bug.cgi?id=1100311
* https://bugzilla.redhat.com/show_bug.cgi?id=1120336

The modified tests were run against build:
 * Satellite-6.0.4-RHEL-6-20140730.0

```bash
$ nosetests -c robottelo.properties tests/foreman/cli/test_org.py:TestOrg.test_bugzilla_1076568_1 tests/foreman/cli/test_org.py:TestOrg.test_bugzilla_1076568_2 tests/foreman/cli/test_org.py:TestOrg.test_bugzilla_1076568_3 tests/foreman/cli/test_org.py:TestOrg.test_bugzilla_1061658
nose.config: INFO: Ignoring files matching ['^\\.', '^_', '^setup\\.py$']
@test: Delete organization by name ... ok
@test: Delete organization by ID ... ok
@test: Delete organization by label ... ok
@Test: Organization delete fails with 500 Server / Candlepin 404 error ... ok

Ran 4 tests in 106.166s

OK
$ nosetests -c robottelo.properties -m test_positive_delete_1 tests/foreman/cli/test_org.py
nose.config: INFO: Ignoring files matching ['^\\.', '^_', '^setup\\.py$']
@test: Create organization with valid values then delete it ... ok
@test: Create organization with valid values then delete it ... ok
@test: Create organization with valid values then delete it ... ok
@test: Create organization with valid values then delete it ... ok

Ran 4 tests in 106.037s

OK
$ nosetests -c robottelo.properties -m test_positive_delete_2 tests/foreman/cli/test_org.py
nose.config: INFO: Ignoring files matching ['^\\.', '^_', '^setup\\.py$']
@test: Create organization with valid values then delete it ... ok
@test: Create organization with valid values then delete it ... ok
@test: Create organization with valid values then delete it ... ok
@test: Create organization with valid values then delete it ... ok

Ran 4 tests in 111.509s

OK
$ nosetests -c robottelo.properties -m test_positive_delete_3 tests/foreman/cli/test_org.py
nose.config: INFO: Ignoring files matching ['^\\.', '^_', '^setup\\.py$']
@test: Create organization with valid values then delete it ... ok
@test: Create organization with valid values then delete it ... ok
@test: Create organization with valid values then delete it ... ok
@test: Create organization with valid values then delete it ... ok

Ran 4 tests in 111.231s

OK
```