toolsSuite.TestFindToolsNotFound panics with 2.0-alpha1

[Cheryl Jennings]

PANIC: tools_test.go:196: toolsSuite.TestFindToolsNotFound

... Panic: value method params.Error.ErrorCode called using nil *Error pointer (PC=0x40EFAD)

/usr/lib/go/src/pkg/runtime/panic.c:248
  in panic
/usr/lib/go/src/pkg/runtime/error.go:123
  in panicwrap
<autogenerated>:2
  in Error.ErrorCode
/home/cherylj/Canonical/Juju/src/github.com/juju/juju/apiserver/params/apierror.go:94
  in ErrCode
/home/cherylj/Canonical/Juju/src/github.com/juju/juju/apiserver/params/apierror.go:121
  in IsCodeNotFound
/usr/lib/go/src/pkg/runtime/asm_amd64.s:361
  in call32
/usr/lib/go/src/pkg/reflect/value.go:411
  in Value.Call
/home/cherylj/Canonical/Juju/src/github.com/juju/testing/checkers/bool.go:75
  in satisfiesChecker.Check
tools_test.go:203
  in toolsSuite.TestFindToolsNotFound
/usr/lib/go/src/pkg/reflect/value.go:411
  in Value.Call
/usr/lib/go/src/pkg/runtime/proc.c:1445
  in goexit
OOPS: 132 passed, 1 PANICKED

PANIC: client_test.go:2209: clientSuite.TestClientFindTools
... Panic: value method params.Error.ErrorCode called using nil *Error pointer (PC=0x40EFAD)

/usr/lib/go/src/pkg/runtime/panic.c:248
  in panic
/usr/lib/go/src/pkg/runtime/error.go:123
  in panicwrap
<autogenerated>:2
  in Error.ErrorCode
/home/cherylj/Canonical/Juju/src/github.com/juju/juju/apiserver/params/apierror.go:94
  in ErrCode
/home/cherylj/Canonical/Juju/src/github.com/juju/juju/apiserver/params/apierror.go:121
  in IsCodeNotFound
/usr/lib/go/src/pkg/runtime/asm_amd64.s:361
  in call32
/usr/lib/go/src/pkg/reflect/value.go:411
  in Value.Call
/home/cherylj/Canonical/Juju/src/github.com/juju/testing/checkers/bool.go:75
  in satisfiesChecker.Check
client_test.go:2212
  in clientSuite.TestClientFindTools
/usr/lib/go/src/pkg/reflect/value.go:411
  in Value.Call
/usr/lib/go/src/pkg/runtime/proc.c:1445
  in goexit
OOPS: 178 passed, 1 PANICKED

[Cheryl Jennings (cherylj)]

PR: https://github.com/juju/juju/pull/3955