Issue 2934: export with uid

[codexnull]

Include actual UIDs in export instead of "_:uid" blanks. Fixes #2934.

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This change is 

[martinmr]

Reviewed 4 of 4 files at r1.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @codexnull)

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worker/export.go, line 73 at r1 (raw file):

// UIDs like 0x1 look weird but 64-bit ones like 0x0000000000000001 are too long.
var uidFmtStr = "<0x%x>"

I thought based on the discussion in the issue that this was going to be an option and the default was still going to be blank nodes.

[codexnull]

Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @martinmr)

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worker/export.go, line 73 at r1 (raw file):

Previously, martinmr (Martin Martinez Rivera) wrote…

I thought based on the discussion in the issue that this was going to be an option and the default was still going to be blank nodes.

Yeah, but during the stand-up @manishrjain said to use the UID.

[manishrjain]

Reviewed 4 of 4 files at r1.
Reviewable status: all files reviewed, 2 unresolved discussions (waiting on @codexnull and @martinmr)

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dgraph/cmd/live/batch.go, line 140 at r1 (raw file):

		time.Sleep(dur)
	case err != y.ErrAborted && err != y.ErrConflict:
		fmt.Printf("Error while mutating. %v\n", s.Message())

switch to colon.

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worker/export.go, line 73 at r1 (raw file):

Previously, codexnull (Javier Alvarado) wrote…

Yeah, but during the stand-up @manishrjain said to use the UID.

Yup, UID directly for every export.

[codexnull]

Reviewable status: 3 of 4 files reviewed, 2 unresolved discussions (waiting on @manishrjain and @martinmr)

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dgraph/cmd/live/batch.go, line 140 at r1 (raw file):

Previously, manishrjain (Manish R Jain) wrote…

switch to colon.

Done.