Fix ipv6 connection hangs when in v4 environment

[ayanamist]

Since connection will be reset to USE_IPV4_IPV6_RANDOM when connection failed even in pure v4 environment.

https://github.com/DrKLO/Telegram/blob/0e17caa7a6facd8220077ee708c4acc942a175d1/TMessagesProj/jni/tgnet/Connection.cpp#L699-L702

However, it does not reset lastProtocolUsefullData correctly if connectionType is not ConnectionTypeGeneric (usually problem occurs when ConnectionTypeGenericMedia) and lastProtocolUsefullData will be set false only here.

https://github.com/DrKLO/Telegram/blob/0e17caa7a6facd8220077ee708c4acc942a175d1/TMessagesProj/jni/tgnet/Connection.cpp#L299-L311

So it always connect as ipv6 if lastProtocolUsefullData is true and RAND_bytes got 0, 3, 6 even there is no ipv6 capability.

I try to fix it using always reset lastProtocolUsefullData to false when USE_IPV4_IPV6_RANDOM is meet.