fix default account addr prefix

[happlins]

Description

The default cosmos prefix is still used instead of the eth prefix set through config.

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For contributor use:

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• Code follows the module structure standards.
• Wrote unit and integration tests
• Updated relevant documentation (docs/) or specification (x/<module>/spec/)
• Added relevant godoc comments.
• Added a relevant changelog entry to the Unreleased section in CHANGELOG.md
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For admin use:

• Added appropriate labels to PR (ex. WIP, R4R, docs, etc)
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• Squashed all commits, uses message "Merge pull request #XYZ: [title]" (coding standards)

[CLAassistant]

All committers have signed the CLA.

[codecov]

Codecov Report

Merging #472 into development will not change coverage.
The diff coverage is 100.00%.

@@             Coverage Diff              @@
##           development     #472   +/-   ##
============================================
  Coverage        69.92%   69.92%           
============================================
  Files               38       38           
  Lines             2487     2487           
============================================
  Hits              1739     1739           
  Misses             617      617           
  Partials           131      131           

Impacted Files	Coverage Δ
x/evm/client/cli/utils.go	74.07% <100.00%> (ø)

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[fedekunze]

thanks @2016-huanglins