Data race detected by travis

[jrick]

==================
WARNING: DATA RACE
Write at 0x00c420077701 by goroutine 20:
  testing.(*common).setRan()
      /home/travis/.gimme/versions/go1.8.1.linux.amd64/src/testing/testing.go:433 +0x97
  testing.(*common).setRan()
      /home/travis/.gimme/versions/go1.8.1.linux.amd64/src/testing/testing.go:429 +0xea
  testing.(*common).setRan()
      /home/travis/.gimme/versions/go1.8.1.linux.amd64/src/testing/testing.go:429 +0xea
  testing.tRunner.func1()
      /home/travis/.gimme/versions/go1.8.1.linux.amd64/src/testing/testing.go:650 +0x48c
  testing.tRunner()
      /home/travis/.gimme/versions/go1.8.1.linux.amd64/src/testing/testing.go:659 +0x123

Previous read at 0x00c420077701 by main goroutine:
  testing.runTests()
      /home/travis/.gimme/versions/go1.8.1.linux.amd64/src/testing/testing.go:890 +0x538
  testing.(*M).Run()
      /home/travis/.gimme/versions/go1.8.1.linux.amd64/src/testing/testing.go:822 +0x1c3
  main.main()
      github.com/decred/dcrwallet/wallet/udb/_test/_testmain.go:50 +0x20f

Goroutine 20 (running) created at:
  testing.(*T).Run()
      /home/travis/.gimme/versions/go1.8.1.linux.amd64/src/testing/testing.go:697 +0x543
  github.com/decred/dcrwallet/wallet/udb.TestUpgrades.func1()
      /home/travis/gopath/src/github.com/decred/dcrwallet/wallet/udb/upgrades_test.go:81 +0x17d
==================

[jrick]

Appears to be unrelated to any dcrwallet code that is included in the main package. Looks like either a race in the testing package or incorrect usage in a test.

[jrick]

Haven't seen this since and it doesn't look a defect in any of our code.

[jrick]

Reopening because I have a workaround (or what should have been the code all along).