Update to support auth token format in 2018.1

[BigCheeZ]

I attempted to install TC "2018.1" using these settings:

teamcity_server_version: "2018.1" teamcity_server_sha256: "d16ec0a4693cf4203d5e201cedf00e7a1559efaec98f54d018e67a3a17ad893d"

The role was failing when on the "Create Admin User" step and I traced it to not having the proper auth token. From the logs I could see that the auth token in 2018.1 does not have double-quotes around it so the grep and cut were not working. I updated the auth token extraction step to support the new format. I have not tried this on an earlier TC build but I did locally test adding double-quotes on both sides of the token.