release semaphore which was not used before

In this line
https://github.com/Oryx-Embedded/CycloneTCP/blob/1976f5905ef6817c2e8a60b10b04729e205ebae9/http/http_server.c#L331

you are referencing to connection->serverContext in the else-path which gets assigned in the if-section.

did you mean this instead?
```
osReleaseSemaphore(&context->semaphore);
```
