(PUP-897) Allow rpm package provider to query by virtual package name.

Some providers that inherit from the rpm provider, such as the yum provider, do
a query after installing a package. If the package is specified by a virtual name,
the yum provider installs the package successfully, but the base rpm provider
implementation fails to query the installed package. This causes a confusing
"could not find package" error even though the package was installed.

Passing the '--whatprovides' option to rpm when performing a query instructs rpm
to locate packages that provide the given virtual name. This enables child providers
to install by virtual package name without errors.
Merge pull request #2370 from peterhuene/master

(PUP-897) Allow rpm package provider to query by virtual package name.