provider/maas: data races

[Dave Cheney]

==================
WARNING: DATA RACE
Write by goroutine 87:
  runtime.mapdelete()
      /home/dfc/go/src/runtime/hashmap.go:513 +0x0
  launchpad.net/gomaasapi.fileHandler()
      /home/dfc/src/launchpad.net/gomaasapi/testservice.go:1134 +0x10b
  launchpad.net/gomaasapi.filesHandler()
      /home/dfc/src/launchpad.net/gomaasapi/testservice.go:1077 +0x7ea
  launchpad.net/gomaasapi.NewTestServer.func3()
      /home/dfc/src/launchpad.net/gomaasapi/testservice.go:519 +0x4b
  net/http.HandlerFunc.ServeHTTP()
      /home/dfc/go/src/net/http/server.go:1433 +0x47
  net/http.(*ServeMux).ServeHTTP()
      /home/dfc/go/src/net/http/server.go:1710 +0x212
  net/http/httptest.(*waitGroupHandler).ServeHTTP()
      /home/dfc/go/src/net/http/httptest/server.go:200 +0xfe
  net/http.serverHandler.ServeHTTP()
      /home/dfc/go/src/net/http/server.go:1873 +0x206
  net/http.(*conn).serve()
      /home/dfc/go/src/net/http/server.go:1372 +0x117c

Previous write by goroutine 90:
  runtime.mapdelete()
      /home/dfc/go/src/runtime/hashmap.go:513 +0x0
  launchpad.net/gomaasapi.fileHandler()
      /home/dfc/src/launchpad.net/gomaasapi/testservice.go:1134 +0x10b
  launchpad.net/gomaasapi.filesHandler()
      /home/dfc/src/launchpad.net/gomaasapi/testservice.go:1077 +0x7ea
  launchpad.net/gomaasapi.NewTestServer.func3()
      /home/dfc/src/launchpad.net/gomaasapi/testservice.go:519 +0x4b
  net/http.HandlerFunc.ServeHTTP()
      /home/dfc/go/src/net/http/server.go:1433 +0x47
  net/http.(*ServeMux).ServeHTTP()
      /home/dfc/go/src/net/http/server.go:1710 +0x212
  net/http/httptest.(*waitGroupHandler).ServeHTTP()
      /home/dfc/go/src/net/http/httptest/server.go:200 +0xfe
  net/http.serverHandler.ServeHTTP()
      /home/dfc/go/src/net/http/server.go:1873 +0x206
  net/http.(*conn).serve()
      /home/dfc/go/src/net/http/server.go:1372 +0x117c

Goroutine 87 (running) created at:
  net/http.(*Server).Serve()
      /home/dfc/go/src/net/http/server.go:1923 +0x455

Goroutine 90 (running) created at:
  net/http.(*Server).Serve()
      /home/dfc/go/src/net/http/server.go:1923 +0x455
==================
OK: 154 passed
PASS
Found 1 data race(s)
FAIL github.com/juju/juju/provider/maas 13.986s

[Martin Packman (gz)]

Had an actual test error from what I assume is this problem on master:

<http://reports.vapour.ws/releases/issue/569e081a749a565a7d735ed2>

[Cheryl Jennings (cherylj)]

PR: https://github.com/juju/juju/pull/4146