Fixing session cannot be create

[geeknection]

When killing a connection with the rtmp server or when turning off the computer while doing a transmission, if you try to transmit again after turning on the computer or going back to the internet, the server does not accept because it informs you that a connection already exists. This pull request fixed that.

[illuspas]

This is a good improvement. However, please pay attention to the following issues.

1. Do not use the dev branch to do this, it is obsolete.
2. This will cause multiple streams with the same name to send data at the same time.
3. Conditional judgment should be added before this operation, such as same ip, same parameters, passing security authentication, etc.