Fix missing blob line permalink updater on blob:show

What does this MR do?

MR that introduced the changes overall: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/9461

• Generalize blob setup to share between projects:blob:show and projects:blob:blame. This used to be handled by one case but https://gitlab.com/gitlab-org/gitlab-ce/commit/e0fe2834ebe6d9678444c8a10b79ca093f944232#dc2de5a9f57ef8263663b3130fd53e8f3821a552_252_259 split it up

Are there points in the code the reviewer needs to double check?

• Are we okay with this generalized initBlob?

Why was this MR needed?

Line permalink updating not working on blob show pages. Which also causes test failures

This seems to have introduced legitimate failures on master: https://gitlab.com/gitlab-org/gitlab-ce/builds/12138972

@rspeicher, https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/9461#note_25288831

Either a bad conflict resolution in the merge commit or git didn't pick up the conflicts during the merge to master. Looks good in my MR: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/9461/diffs#dc2de5a9f57ef8263663b3130fd53e8f3821a552_252_253 but the problem occurs in the merge commit: https://gitlab.com/gitlab-org/gitlab-ce/commit/08f7e49d2980dcb23902cec3324a61dd8ba9c0e9#dc2de5a9f57ef8263663b3130fd53e8f3821a552_273_274

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Is git missing an actual conflict a known pitfall?

Here is the commit history (top 3 commits in question): https://gitlab.com/gitlab-org/gitlab-ce/commits/08f7e49d2980dcb23902cec3324a61dd8ba9c0e9/app/assets/javascripts/dispatcher.js

My MR didn't have any conflicts and worked properly, code under projects:blob:show and projects:blame:show switch cases: https://gitlab.com/gitlab-org/gitlab-ce/commit/c0242485393fe93397ee18889bc5345b67d5ea0d#dc2de5a9f57ef8263663b3130fd53e8f3821a552_252_253

But in the merge commit, things change, code only under projects:blame:show (was a MWPS): https://gitlab.com/gitlab-org/gitlab-ce/commit/08f7e49d2980dcb23902cec3324a61dd8ba9c0e9#dc2de5a9f57ef8263663b3130fd53e8f3821a552_273_274

The commit that made conflicting changes (wasn't detected): https://gitlab.com/gitlab-org/gitlab-ce/commit/e0fe2834ebe6d9678444c8a10b79ca093f944232#dc2de5a9f57ef8263663b3130fd53e8f3821a552_252_259

@MadLittleMods, https://gitlab.slack.com/archives/development/p1489446888222228

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It’s not technically a conflict since the commits didn’t touch the same lines 😞

@DouweM, https://gitlab.slack.com/archives/development/p1489447115261970

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Tests
  • All builds are passing
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?