(maint) Stop referencing undefined variable in package testing

With strict mode on, this test fails instead of warning when
`$releasever` is not defined. Removing the variable allows the
test to complete successfully. This will allow acceptance tests
to run for PA-4881.

Author: tvpartytonight

acceptance/tests/provider/package/rpm_ensure_install_multiversion_package.rb

@@ -11,7 +11,7 @@
 
   repo_content = <<-REPO
 [local]
-name=EL-$releasever - test packages
+name=EL-releasever - test packages
 baseurl=file:///tmp/el-repo
 enabled=1
 gpgcheck=0