Fix GIT #516 and 517 return success when respond with error

[sgbihu]

Root cause

1. The return value indecate the read/write request send successfully.
2. The subscribe will ignore the response and this will not be fixed.

Solution

1. Add the error detect based on read/write response.

Changed files
BLECallbacks.cpp - Delete the error check for read response.
BLECharacteristicImp.cpp

• Add the error check.
• Optimize the memory allocate and clear the allocated memory.
  BLECharacteristicImp.h - Add varibles to flag the response error

[sandeepmistry]

The subscribe will ignore the response and this will not be fixed.

Will this be fixed later?

[sgbihu]

This always ignore the response in the stack. So the application can't get the result. This is the stack's limitation. And the return value stand for the gatt ccc write request send out. And it is an unblock call. I think we will not fix for the subscribe API.

[sandeepmistry]

Is this a limitation of the firmware?

And it is an unblock call. I think we will not fix for the subscribe API.

I expect characteristic.subscribe() and characteristic.unsubscribe() to block.

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