Use node 7.8 specifically for ci job

Signed-off-by: Snorre Magnus Davøen <snorre.davoen@nsd.uib.no>
1 job for master in 1 minute and 27 seconds
Status Job ID Name Coverage
  Test
failed #8767
test

00:01:27

 
Name Stage Failure
failed
test Test There is an unknown failure, please try again
npm ERR! If you need help, you may report this error at:
npm ERR! <https://github.com/npm/npm/issues>

npm ERR! Please include the following file with any support request:
npm ERR! /root/.npm/_logs/2017-05-09T13_03_29_639Z-debug.log

error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
ERROR: Job failed: exit code 1