remove query function:QueryProtocolVersion

[summerpro]

From：cosmos/ethermint#575

• Targeted PR against correct branch (see CONTRIBUTING.md)

• Linked to github-issue with discussion and accepted design OR link to spec that describes this work.

• Wrote tests

• Updated relevant documentation (docs/)

• Added a relevant changelog entry to the Unreleased section in CHANGELOG.md

• Reviewed Files changed in the github PR explorer

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For Admin Use:

• Added appropriate labels to PR (ex. wip, ready-for-review, docs)
• Reviewers Assigned
• Squashed all commits, uses message "Merge PR #XYZ: [title]" (coding standards)

[codecov-io]

Codecov Report

Merging #481 (1fae934) into dev (6c7c1f4) will not change coverage.
The diff coverage is 0.00%.

@@           Coverage Diff           @@
##              dev     #481   +/-   ##
=======================================
  Coverage   68.24%   68.24%           
=======================================
  Files         254      253    -1     
  Lines       13769    13769           
=======================================
  Hits         9396     9396           
  Misses       3870     3870           
  Partials      503      503           

Impacted Files	Coverage Δ
app/rpc/namespaces/eth/api.go	0.00% <0.00%> (ø)
app/rpc/namespaces/web3/api.go	0.00% <0.00%> (ø)

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