mdns_search_once_t::lock is used to synchronize tasks (taken by one
task and given by the other) so it should not be a mutex.
Convert to semaphore, and rename to indicate its purpose.
packets scheduled to transmit are pushed to action queue and removed from tx_queue_head structure, which is searched for all remaining services and while service is removed, then service questions/asnwers are also removed from this structure. This update fixes possible crash when packet is pushed to action queue, and when service is removed, its answers are removed from tx_queue_head, but not from action queue. this could lead to a crash when the packet is poped from action queue containing questions/answers to already removed (freed) service
Allocation was happening later, causing possible use of stack variables
of caller function, which could be invalid.
Signed-off-by: Piyush Shah <piyush@espressif.com>
