[conformal/btcwallet] 417aa6: Add a missing mutex lock/unlock.

[Josh Rickmar]

  Branch: refs/heads/master
  Home:   https://github.com/conformal/btcwallet
  Commit: 417aa63534ef7315871bd08da3b60f6e2aeed081
      
https://github.com/conformal/btcwallet/commit/417aa63534ef7315871bd08da3b60f6e2aeed081
  Author: Josh Rickmar <jr...@conformal.com>
  Date:   2013-11-21 (Thu, 21 Nov 2013)

  Changed paths:
    M account.go

  Log Message:
  -----------
  Add a missing mutex lock/unlock.

Spotted by dhill.