Syncing ECM release number with KF5

[Stephen Kelly]

Hello,

ECM release numbers are in sync with KF5 release numbers, except for the 
major component.

This means that if you want to build the 5.x.y release you have to download 
the 1.x.y release of ECM. That doubles the complexity of your script which 
downloads the tarball to build it. 

That is bad and it is not necessary.

Let's sync the major number for the next release.

At some point the reason to make them out of sync was to be able to make ECM 
releases more frequently. That is very rare because KF5 releases are 
happening every month. If ECM needs to make an out of band release, it can 
use the 4th version number component.

Thanks,

Steve.