- sync charmhelpers with fix-alpha helpers
- fix up code where the alpha comparisons are done
- fix tests which assumed mocks would just work on os_release()
Change-Id: I3d1a8993286f0e7a1037c03e6711015883f1b615
Related-Bug: #1659575
The charm-helpers project have re-licensed to Apache 2.0
inline with the agreed licensing approach to intefaces,
layers and charms generally.
Resync helpers to bring charmhelpers inline with charm
codebase.
Change-Id: I7d884baad621eaa22cdef4f4b980044616116513
