Check response status when posting telemtry data.

[arijitAD]

When posting telemetry data check the response status and on error return an appropriate error.
Also, updating the telemetry ticker from one minute to ten minute.

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This change is 

[martinmr]

Reviewed 3 of 3 files at r1.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @arijitAD and @manishrjain)

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dgraph/cmd/zero/zero.go, line 101 at r1 (raw file):

	start := time.Now()

	ticker := time.NewTicker(time.Minute * 10)

Include this change in the description.

[arijitAD]

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

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dgraph/cmd/zero/zero.go, line 101 at r1 (raw file):

Previously, martinmr (Martin Martinez Rivera) wrote…

Include this change in the description.

Done.

[manishrjain]

Reviewed 3 of 3 files at r1.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @martinmr)