local storage test intermittent failure

[William Reade]

----------------------------------------------------------------------
FAIL: backend_test.go:34: backendSuite.SetUpSuite

backend_test.go:38:
    c.Assert(err, IsNil)
... value *errors.errorString = &errors.errorString{s:"cannot start listener: listen tcp 127.0.0.1:60006: address already in use"} ("cannot start listener: listen tcp 127.0.0.1:60006: address already in use")

----------------------------------------------------------------------
PANIC: backend_test.go:43: backendSuite.TearDownSuite

... Panic: runtime error: invalid memory address or nil pointer dereference (PC=0x41149C)

/home/william/go/src/pkg/runtime/proc.c:1443
  in panic
/home/william/go/src/pkg/runtime/runtime.c:128
  in panicstring
/home/william/go/src/pkg/runtime/thread_linux.c:209
  in sigpanic
backend_test.go:44
  in backendSuite.TearDownSuite

----------------------------------------------------------------------
FAIL: storage_test.go:18: storageSuite.TestPersistence

storage_test.go:23:
    c.Assert(err, IsNil)
... value *errors.errorString = &errors.errorString{s:"cannot start listener: listen tcp 127.0.0.1:60007: address already in use"} ("cannot start listener: listen tcp 127.0.0.1:60007: address already in use")

OOPS: 0 passed, 2 FAILED, 1 FIXTURE-PANICKED, 4 MISSED
--- FAIL: TestLocal (0.00 seconds)
FAIL
FAIL launchpad.net/juju-core/environs/local 0.025s

[Dimiter Naydenov (dimitern)]

 I got this again: http://paste.ubuntu.com/5596073/