free slot after getting event from url-download

free slot after getting event from url-download

[Title] free slot(memory) after getting event (STOP) or broken socket
[Issue#] N/A
[Problem] client can't receive any event if downloading is too fast.
[Cause] free slot before client accepting event
[Solution] maintain socket and slot(memory) including the info till client accept all event.
[SCMRequest] N/A

[Title] apply the flag for timeout
[Issue#] N/A
[Problem] so many called
[Cause] after finished download, main loop should ignore it.
[Solution] change the flag only when deal events really.
[SCMRequest] N/A

Change-Id: I55e843eca9770d099fcbeb176c53735002adb407