Let Camlistore build on Solaris

The biggest obstacle is that syscall lacks Mkfifo on Solaris
(I've opened issue 8609 on Go for this).
Now I provide the same implementation for it as there is on Linux:
call Mknod.

github.com/cznic/fileutil needs IsEOF, so I've copied the plan9
(hole punching is stubbed out) implementation.

github.com/lib/pq: I've added solaris as a posix build tag.

Change-Id: Id667c488606a274849dc9b0af76abf1daeab5ad7
wip docker s3

Change-Id: I39413252b079e6c0f7fe2f038f3388de38b1317b