rebuilding / upgrading a package at the same version

[Riccardo Mottola]

Hi,

how can I rebuild a port without it being detected as "upgrade" because 
it stays at the same version?
It may happen because rev-upgrade detects it but fails to build (e.g. 
want to change the compiler) or because for some strange reason 
rev-upgrade fails to detect and I want to rebuild it anyway.

upgrade maintains variants and also the status if the package was 
requested or not, as well as not needing to mess with dependencies.

Riccardo