acu66732 fix child_account update href 

This needs to be handled specially because there is no real ChildAccount resource.
On the other hand, the API does not support Account#update either.
Therefore, we can pretend that we are always dealing with a ChildAccount resource.

Usage:
child_account = @client.child_accounts.index.last
child_account.update(:name => "Account 62840")
Merge remote-tracking branch 'origin/yellow_12_13_66732_fix_child_account_update'

Conflicts:
	lib/right_api_client/resource_detail.rb
Merge remote-tracking branch 'origin/master'