Fixed handling cancelled bonding for read/write operations

[philips77]

This PR fixes #552, again.

Write and read requests trigger bonding when sent using an unsecured link to a protected attribute. If bonding fails, e.g. it's cancelled, there are 2 things happening:

1. Read characteristic and Read descriptor requests get status 137 in onCharacteristicRead callback. This will be ignored.
2. Write characteristic and Write descriptor requests don't get such callback. They don't get any callback, actually.

In both cases, the bond state broadcast receiver gets transition BOND-BONDING -> BOND_NONE. This PR adds a code to fail awaiting request of write/read type.

If no GATT operation is performed withing 3 seconds after bonding fails, the device gets disconnected (Android disconnects, not the library). However, if there is any GATT operation enqueued and will be executed, the phone continues as if nothing happened. It can trigger bonding again and again. At some point, if bonding state changed to BOND_NONE, call to a protected attribute will generate status 5 (BluetoothGatt.GATT_INSUFFICIENT_AUTHENTICATION). This means, that Android will not try to bond again, and the request is getting failed immediately.

[philips77]

I didn't manage to get error 8 during tests, but I will threat it just as state 5. I think it may be called when the security is insufficient (bonded without MITM, but MIMT required, etc.). This could be checked in the future.