Remove the comments from being within a command,

[martynbristow]

Docker rejects multi-line commands which contain a comment:
The error is:
Martyns-MBP:5.6 martyn$ docker build .
Sending build context to Docker daemon 96.77 kB
Error response from daemon: Unknown instruction: --ENABLE-FTP

Or:
Martyns-MBP:5.6 martyn$ docker build .
Sending build context to Docker daemon 96.77 kB
Error response from daemon: Unknown instruction: &&

[martynbristow]

This will solve issue: #336

[yosifkit]

I think we'd rather fix this in docker itself, since 1.13 is still a release candidate and effects more than just the php Dockerfile. We have filed an issue: moby/moby#29005.

[tianon]

Yeah, this is something that will be fixed in Docker itself before 1.13 GA. 👍