Include architecture in RPM/yum commands

With yum and RPM on machines that support multiple architectures, you
can limit each operation to one of those architectures by specifying
package names as `[package].[arch]`.  If you don't, many of the commands
will return information about all available architectures.  This
confuses some of our parsers, so now we explicitly only ever try to
query, build, or install packages for the current architecture.