I am going to deprecate backport-util-concurrent in F19. backport-util-concurrent is an implementation of java.util.concurrent.*. It used to be useful when Java 1.5 wasn't widely used, but now it's no longer needed. Please remove backport-util-concurrent dependency from eucalyptus package. You can see bug #875162 for example how this could be done.
Upstream bug report: https://eucalyptus.atlassian.net/browse/EUCA-4254
Fixed in eucalyptus version 3.2.0-0.5.20121210git5ab7257. Closing.