[packages/rpm-build-tools] Use rpm-specdump if it exists, rpm.org rpm can't do 'rpm dump %prep'

[Elan Ruusamäe]

On 26.02.2021 09:59, baggins wrote:

> commit efec12ac5420b483fb368b05ba3c7f04c06d05ab
> Author: Jan Rękorajski <baggins at pld-linux.org>
> Date:   Fri Feb 26 08:58:12 2021 +0100
>
>      Use rpm-specdump if it exists, rpm.org rpm can't do 'rpm dump %prep'

why even bother supporting configurations without rpm-specdump installed?

abort script if tool is missing and move along.


ps: is the note about "Icon:" tag even valid?  does rpm-specdump fail 
too? i don't think we have any .spec with Icon: present