Removing broken CLI test for Host.

This test was badly merged (it uses API calls for what should be a CLI
test) and it is also obsolete as systems are now called Content Host.
I'd like to delete this test (and avoid a false failure from our builds)
until I add a new set of CLI tests for Content Hosts.
Added negative tests and removed few stubs as UI changed
reduce test execution speed for remove tests
fix the subnet assert for remove tests
added verification, that repo was not synchronized
added verification, that repo finished synchroning
remove todo
Added the success notifs for subnet delete
Merge pull request #783 from AdamSaleh/cli-assert-repo-sync

Cli assert repo sync
Merge pull request #782 from kbidarkar/fix-subnet-assert3

fix the subnet assert for remove tests
Merge branch 'master' into make-remove-tests-faster

Conflicts:
	tests/foreman/ui/test_subnet.py
Merge pull request #780 from kbidarkar/make-remove-tests-faster

UI: reduce test execution speed for remove tests
Merge pull request #775 from omaciel/delete-cli-host-test

Removing broken CLI test for Host.
Merge pull request #776 from kbidarkar/add-cli-promote-tests

Added negative tests and removed few stubs as UI changed