Update rules_go, bazel_gazelle, and go-ethereum to Support Go 1.11

[prestonvanloon]

The latest version of rules_go and bazel_gazelle support go 1.11 which has a lot of nice features.

I don't foresee any issues, but please checkout this branch and build it on your local machine before clicking approve.

Need

• Approval build from MacOS
• Approval build from Linux

I've built and ran tests for ubuntu, but I haven't tested on MacOS.

[codecov]

Codecov Report

Merging #490 into master will decrease coverage by 0.35%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #490      +/-   ##
==========================================
- Coverage   78.27%   77.91%   -0.36%     
==========================================
  Files          39       39              
  Lines        2536     2536              
==========================================
- Hits         1985     1976       -9     
- Misses        378      385       +7     
- Partials      173      175       +2

Impacted Files	Coverage Δ
beacon-chain/rpc/service.go	92.85% <0%> (-4.77%)	⬇️
beacon-chain/sync/initial-sync/service.go	68.33% <0%> (-4.17%)	⬇️

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[terencechain]

I got the following errors from bazel run //:gazelle

git≠prestonvanloon-update-rules-go-and-gazelle)❱✔≻ bazel run //:gazelle 
Starting local Bazel server and connecting to it...
..............................
Analyzing: target //:gazelle (7 packages loaded)
Analyzing: target //:gazelle (7 packages loaded)
ERROR: /private/var/tmp/_bazel_terencetsao/3136447ae55d487a443f50acb4025ea7/external/go_sdk/BUILD.bazel:20:1: @go_sdk//:srcs: invalid label 'src/cmd/go/testdata/mod/rsc.io_!c!g!o_v1.0.0.txt' in element 813 of attribute 'srcs' in 'filegroup' rule: invalid target name 'src/cmd/go/testdata/mod/rsc.io_!c!g!o_v1.0.0.txt': target names may not contain '!'
ERROR: /private/var/tmp/_bazel_terencetsao/3136447ae55d487a443f50acb4025ea7/external/go_sdk/BUILD.bazel:57:1: @go_sdk//:files: invalid label 'src/cmd/go/testdata/mod/rsc.io_!c!g!o_v1.0.0.txt' in element 1242 of attribute 'srcs' in 'filegroup' rule: invalid target name 'src/cmd/go/testdata/mod/rsc.io_!c!g!o_v1.0.0.txt': target names may not contain '!'
ERROR: Analysis of target '//:gazelle' failed; build aborted: error loading package '@go_sdk//': Package '' contains errors

[prestonvanloon]

Oh boy! Ok, I'll look into that.

Meanwhile, I've created #491 to have travis catch these types of things.

[terencechain]

Works on a mac with bazel-0.16.1
Was able to build validator and run gazelle.

[nisdas]

LGTM

[rauljordan]

Confirmed works on ubuntu 16.04