E2E Test Maintenance

[patthiel]

• adds fixes for volumes tests
• fixes backups tests
• Fixes oauth clients tests (uses more reliable selector assertion)
• Hardcode volume creation region.

To Test

• Test the specs in this PR.

yarn && yarn start
yarn selenium
yarn e2e --file e2e/specs/create/create-volume.spec.js && yarn e2e --file
e2e/specs/volumes/volume-configuration.spec.js && yarn e2e --file e2e/specs/linodes/detail/backups.spec.js && yarn e2e --file e2e/specs/profile/clients.spec.js && yarn e2e --file e2e/specs/profile/tokens.spec.js

These tests are also going to be running on CI, PM me for the results.

[coveralls]

Coverage increased (+0.009%) to 27.753% when pulling cdd4756 on patthiel:07-12-test-maintenance into 0c4dd38 on linode:develop.