Pathpol: Change policy in options

[worxli]

Change policy in pathpol.Options to ExtPolicy. This is required so an option can not only have anonymous policies, but also extend others.

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This change is 

[lukedirtwalker]

Reviewed 1 of 3 files at r1, 2 of 2 files at r2.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @sustrik and @worxli)

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go/lib/pathpol/policy_test.go, line 855 at r2 (raw file):

	})
	jsonPol, err := json.Marshal(policy)
	if assert.NoError(t, err) {

we usually just use require.NoError(t, err) so the if isn't needed.

[worxli]

Reviewable status: 2 of 3 files reviewed, all discussions resolved (waiting on @lukedirtwalker and @sustrik)

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go/lib/pathpol/policy_test.go, line 855 at r2 (raw file):

Previously, lukedirtwalker (Lukas Vogel) wrote…

we usually just use require.NoError(t, err) so the if isn't needed.

Done.

[lukedirtwalker]

Reviewed 1 of 1 files at r3.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @sustrik)

[lukedirtwalker]

Reviewed 1 of 1 files at r4.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @sustrik)