make lru_mb optional

[campoy]

Fixes #3850

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This change is 

[pullrequest]

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[pullrequest]

PR does exactly what it says it does in the description. Looked at the C related things in particular and nothing stood out to me at this time.

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Reviewed with ❤️ by PullRequest

[manishrjain]

Got a couple of comments. Please address before merging.

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

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edgraph/config.go, line 105 at r1 (raw file):

		mb := bytes / 1024 / 1024
		if mb > MinAllottedMemory {
			opt.AllottedMemory = float64(mb / 2)

Set it to 25% of total RAM.

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edgraph/config.go, line 106 at r1 (raw file):

		if mb > MinAllottedMemory {
			opt.AllottedMemory = float64(mb / 2)
			fmt.Fprintf(os.Stderr,

Use glog.Infof.

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edgraph/config.go, line 108 at r1 (raw file):

			fmt.Fprintf(os.Stderr,
				"LRU memory (--lru_mb) set to %vMB, 50%% of the total RAM found (%vMB)\n"+
					"For more information on --lru_mb please read https://docs.dgraph.io/deploy/#config\n",

100 chars.

[campoy]

Reviewable status: all files reviewed, 3 unresolved discussions (waiting on @manishrjain)

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edgraph/config.go, line 105 at r1 (raw file):

Previously, manishrjain (Manish R Jain) wrote…

Set it to 25% of total RAM.

Done.

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edgraph/config.go, line 106 at r1 (raw file):

Previously, manishrjain (Manish R Jain) wrote…

Use glog.Infof.

Done.

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edgraph/config.go, line 108 at r1 (raw file):

Previously, manishrjain (Manish R Jain) wrote…

100 chars.

Done.