Fix blueocean/blueocean imaage

[halkeye]

Docker image was unable to actually build due to jessie packages no longer being mirroed

Step 2/26 : RUN apt-get update && apt-get install -y wget git curl zip && rm -rf /var/lib/apt/lists/*
 ---> Running in f7cb5675234d
Get:1 http://security.debian.org jessie/updates InRelease [44.9 kB]
Ign http://deb.debian.org jessie InRelease
Get:2 http://deb.debian.org jessie-updates InRelease [7340 B]
Ign http://deb.debian.org jessie-backports InRelease
Get:3 http://deb.debian.org jessie Release.gpg [2420 B]
Ign http://deb.debian.org jessie-backports Release.gpg
Get:4 http://deb.debian.org jessie Release [148 kB]
Ign http://deb.debian.org jessie-backports Release
Err http://deb.debian.org jessie-backports/main amd64 Packages
  
Err http://deb.debian.org jessie-backports/main amd64 Packages
  
Get:5 http://security.debian.org jessie/updates/main amd64 Packages [824 kB]
Err http://deb.debian.org jessie-backports/main amd64 Packages
  
Get:6 http://deb.debian.org jessie/main amd64 Packages [9098 kB]
Err http://deb.debian.org jessie-backports/main amd64 Packages
  404  Not Found
Fetched 10.1 MB in 7s (1421 kB/s)
W: Failed to fetch http://deb.debian.org/debian/dists/jessie-updates/InRelease  Unable to find expected entry 'main/binary-amd64/Packages' in Release file (Wrong sources.list entry or malformed file)

W: Failed to fetch http://deb.debian.org/debian/dists/jessie-backports/main/binary-amd64/Packages  404  Not Found

E: Some index files failed to download. They have been ignored, or old ones used instead.
The command '/bin/sh -c apt-get update && apt-get install -y wget git curl zip && rm -rf /var/lib/apt/lists/*' returned a non-zero code: 100

This migrates everything to use the default jenkins lts image, so we don't have to do any maintaince work