spec cleanup: remove ignored BuildRoot tag
spec cleanup: remove ignored BuildRoot tag

References:
http://rpm.org/gitweb?p=rpm.git;a=commit;h=6c06519 (~2008)

kgaillot/libqb,ClusterLabs/libqb,kgaillot/libqb,ClusterLabs/libqb,kgaillot/libqb,ClusterLabs/libqb