Jetpack Scan: use "Jetpack" instead of "VaultPress" in SSH Key

[v18]

The generated SSH key finishes with “VaultPress”. Let's have it finish with “Jetpack” instead.

[designsimply]

Tested and confirmed with the following steps:

1. Go to https://wpcalypso.wordpress.com/settings and select a Jetpack-connected site
2. Click Security in the header bar
3. Click Activate or Edit in the Jetpack Scan box
4. Click the "Get your public key string." link (bottom of the box)
5. Check to see whether "VaultPress" or "Jetpack" appears at the end of the string

Result: string ends in "VaultPress"

^{Seen at https://wpcalypso.wordpress.com/settings/security/wildly.disambiguously.com using Firefox 45.0.1 on Mac OS X 10.11.13}

[stale]

This issue has been marked as stale because it hasn't been updated in a while. It will be closed in a week. If you would like it to remain open, can you please comment below and see what you can do to get things moving with this issue? Thanks! 🙏