[SRU precise/trusty] LP:#1838610 -- fix upload numbers in precise/trusty builds

[Andy Whitcroft]

When we backport a version we now universally use ~<series version>.N
(eg ~12.04.1) rather than the previous ~preciseN.  This has exposed a
small parsing issue with the upload number.  This has little to no
effect other than not fully exposing the version in uname -a.  This is
not the canonical version source (/proc/version_signature is preferred)
but it is a change and should be fixed.

Following this email are three patches.  The first is only needed in
precise, the second and third are also needed in trusty.

Proposing for SRU in the next (if any) SRU cycle for precise/linux and
trusty/linux.

-apw