fixes #3712 - change develop versioning scheme to indicate next version

See http://projects.theforeman.org/issues/3712 for the reason behind this.

The key point here is to ensure that the version of our nightly packages indicates it's 1.4, but according to RPM's versioning is less than the first RC and any stable release.  Hopefully I've achieved that.

The nightly builds from Jenkins will continue to append a date and git SHA immediately before the %{?dist}.

Updated wiki docs:
http://projects.theforeman.org/projects/foreman/wiki/RPM_Packaging/diff?utf8=%E2%9C%93&version=37&version_from=35&commit=View+differences
http://projects.theforeman.org/projects/foreman/wiki/Release_Process/diff?utf8=%E2%9C%93&version=71&version_from=69&commit=View+differences

CC @lzap, @skottler and @jmontleon, please ACK.

Replaces #996.