jsonsign: clean up remnants of old secret ring default

http://camlistore.org/issue/368

Change-Id: I2708a97fdffd218f15ed9a1d482712ed7ed07197
Merge "jsonsign: clean up remnants of old secret ring default"
Basic Dockerfile for building everything.

Change-Id: I4e00c9fefc472c10e1103c25884dcef4ff7b4664
Merge branch 'master' of https://camlistore.googlesource.com/camlistore