This commit:
* fixes a crash when handling interecept hook failures which happened when
MULTILIB_GLOBAL_VARIANTS was not set;
* convert dashes to underscores and use sets (so that we make sure the
items are unique) when creating RPM repos;
* uses a regex pattern to search for packages in the feeds list. The
old method could match also strings in the middle. For example: 'rpm'
matched 'kernel-module-lttng-probe-rpm" in qemux86_64 feeds;
* issue a bb.fatal if smart returns error while installing packages.
Otherwise we might end up with an incomplete image...
* fixes the /etc/rpm/platform file creation;
