Upgrade to 1.6.1 upstream release

[gberche-orange]

Upstream upgrade procedure is documented at https://github.com/cloudfoundry-community/etherpad-lite-cf/blob/cloudfoundry/UPDATE.md

Unsuccessfully tried merging upstream 1.6.1 with previous node7 upgrade from @poblin-orange in update_1_6_1 branch.

Failed in https://travis-ci.org/cloudfoundry-community/etherpad-lite-cf/builds/263540878 with

$ mv node_modules/ep_etherpad-lite/node_modules/ep_* node_modules
mv: cannot stat `node_modules/ep_etherpad-lite/node_modules/ep_*': No such file or directory

Would need local building and checking upstream changes.
Moving this into a distinct issue

[gberche-orange]

Made a mistake when handling merge conflict in 3f02e4c where I removed by mistake the ep_ modules from package.json. Need to reapply properly steps documented at https://github.com/cloudfoundry-community/etherpad-lite-cf/blob/cloudfoundry/UPDATE.md

[gberche-orange]

Re-performed the update procedure to 1.6.1 into 9d0f5e9 and https://github.com/cloudfoundry-community/etherpad-lite-cf/releases/tag/1.6.1-cf

Now hitting ether#3117, this could be related to ether#3084 trying to fix ether#3074.

Next steps:

• try to update to latest commits in upstream master. Failed with same symptoms, see traces
  • try running with latest nodejs 6.9.x version instead of nodejs 7. Failed with same symtoms, see traces
  • try building and running with latest nodejs 6.9.x version instead of nodejs 7
    • try reverting Updated npm to 4.0.2 and removed recursive searching for ep-plugins ether/etherpad-lite#3084. Built in 1.6.1-cf-a0aedd679301e5bb75cedf889f91e89e8e5014b7-node69 Failed with infinite recursion (see traces)
• try to stick with etherpad-lite-1.6.0 with node js 6.9.x. Tried in 1.6.0-cf-node169 tag. Now displaying new error traces, along with internal mysql infrastructure issues.
• Dig into Updated npm to 4.0.2 and removed recursive searching for ep-plugins ether/etherpad-lite#3084 to understand if etherpad-lite-cf specifics would be interferring such as https://github.com/cloudfoundry-community/etherpad-lite-cf/blob/1.6.0-cf-node169/.travis.yml#L9-L12 Possibly getting help from @ArthurHlt

[wayglem]

The new release etherpad-lite-cf-1.6.3 supports Node8 which is the LTS version.