fix(linkedin): add retry logic to user info fetching

## What? Why?

Add retry logic to user info fetching because sometimes Linkedin gets back with the following data:
    raw_info: {
      errorCode: 0,
      message: "Could not find person based on: ~",
      requestId: "***************",
      status: 404,
      timestamp: 1393490622830.0
    }

## How was it tested

Locally

## Pre-deployment

- [ ] API is compatible with existing APIs and relevant standards (if applicable)
- [ ] PR contains breaking change
- [ ] PR contains unit tests
- [ ] PR contains integration tests (if suitable)
- [ ] PR passes all tests on Travis (sanity)
- [ ] PR is rebased against recent develop
- [ ] PR is squashed into one commit per logical change
- [ ] PR requires seeding after deployment (if applicable)
- [ ] All changes requested in review have been implemented
- [ ] PR requires QA
- [ ] PR has been QA'ed (if applicable)

## After-deployment

- [ ] Changes have been verified
- [ ] Seeding has been done (if applicable)

review: @dfguo 
cc: