Block/unblock remove- commands and tests.
Block operation before validating it. Remove redundant tests.
Made error msg explicit and cleaned up some tsts.
Added tests to check msg is logged. Cleaned up comments, renamed method for clarity and removed redundant tests.
Organised imports.
Block/unblock remove- commands and tests.
Block operation before validating it. Remove redundant tests.
Made error msg explicit and cleaned up some tsts.
Added tests to check msg is logged. Cleaned up comments, renamed method for clarity and removed redundant tests.
Organised imports.
jc,ErrorIsNil updates and merge conflict resolution.
Merge remote-tracking branch 'origin/prevent-objects-deletion' into prevent-objects-deletion

Conflicts:
	apiserver/client/client_test.go
	cmd/juju/block_test.go
	cmd/juju/destroyenvironment_test.go
	cmd/juju/removemachine_test.go
	cmd/juju/removerelation_test.go
	cmd/juju/removeservice_test.go
	cmd/juju/removeunit_test.go
	juju/testing/conn.go
Merge pull request #1213 from anastasiamac/prevent-objects-deletion

Block/unblock remove- commands and tests.

Customers and stakeholders want to be able to prevent accidental damage to their Juju deployments by preventing juju entity deletion - machine, service, unit, relation. However, all removes can still be forced.

(Review request: http://reviews.vapour.ws/r/523/)