glide: update btcwallet vendor to newest version

This commit updates the version of btcwallet to the newest version
available in roasbeef’s fork. This new version includes the following
changes:
   * a fix for the ping/pong deadlock issue with an expiring session
   * and a preliminary merging of r btcsuite/btcwallet#469 into
roasbeef’s fork

The first change should solve an issue of lnd’s internal wallet
(btcwallet) being disconnected from the local btcd node. And the second
change should improve the reliability/correctness of the wallet as the
wtxmgr (tx/utxo store) and the waddrmgr (key store) are now updated
under a _single_ database transaction.

glide.yaml

@@ -33,7 +33,7 @@ import:
   - hdkeychain
   - txsort
 - package: github.com/roasbeef/btcwallet
-  version: 780d9ff180a119a45437b5835114a991f69fd39f
+  version: 8e06194d49fc1cef9b86dd87c029f8afb37423a0
   subpackages:
   - chain
   - waddrmgr