(cherry picked from commit fc6bccad2603ecac4fa3b67d47965082ddc382f4) ## What changes were proposed in this pull request?
By storing the subscriptions within the loadLogs we can unsubscribe from them which means cancellation of the HTTP request. So that we do not wait the result and do not render the response. Also a small UX fix has been added: a small request indicator in the right bottom corner will be displayed when there is (at least one) a background request. This was for testing purpose but still we need a "request in progress" feedback for the user, I styled a bit. ## How was this patch tested? It was tested manually and by unit tests: ``` PhantomJS 2.1.1 (Mac OS X 0.0.0): Executed 268 of 268 SUCCESS (8.929 secs / 8.843 secs) ✨ Done in 35.98s. ``` Please review [Ambari Contributing Guide](https://cwiki.apache.org/confluence/display/AMBARI/How+to+Contribute) before opening a pull request. [ Full content available at: https://github.com/apache/ambari/pull/2184 ] This message was relayed via gitbox.apache.org for [email protected]
