debuginfo-install: support cases where src.rpm name != binary package name

This depends on my pull request #50.

Main behavioral change can be tested on krb5-libs package from Fedora 21. 
Dependency algorithm changes are visible e.g. on java-1.8.0-openjdk and java-1.8.0-openjdk-headless packages.

I hope it does not break something, I was not able to find any counter-example...