manifest: include yumconfig options in OS customizations

YUMConfig is supported in ImageConfig for RHEL 7.  We now copy the
options over to OSCustomizations and create the stage when necessary.

internal/distro/rhel7/images.go

@@ -157,6 +157,7 @@ func osCustomizations(
 	osc.DNFConfig = imageConfig.DNFConfig
 	osc.DNFAutomaticConfig = imageConfig.DNFAutomaticConfig
 	osc.YUMRepos = imageConfig.YUMRepos
+	osc.YUMConfig = imageConfig.YumConfig
 	osc.SshdConfig = imageConfig.SshdConfig
 	osc.AuthConfig = imageConfig.Authconfig
 	osc.PwQuality = imageConfig.PwQuality

internal/manifest/os.go

@@ -95,6 +95,7 @@ type OSCustomizations struct {
 	Sysctld             []*osbuild.SysctldStageOptions
 	DNFConfig           []*osbuild.DNFConfigStageOptions
 	DNFAutomaticConfig  *osbuild.DNFAutomaticConfigStageOptions
+	YUMConfig           *osbuild.YumConfigStageOptions
 	YUMRepos            []*osbuild.YumReposStageOptions
 	SshdConfig          *osbuild.SshdConfigStageOptions
 	GCPGuestAgentConfig *osbuild.GcpGuestAgentConfigOptions
@@ -459,6 +460,10 @@ func (p *OS) serialize() osbuild.Pipeline {
 		pipeline.AddStage(osbuild.NewYumReposStage(yumRepo))
 	}
 
+	if p.YUMConfig != nil {
+		pipeline.AddStage(osbuild.NewYumConfigStage(p.YUMConfig))
+	}
+
 	if p.GCPGuestAgentConfig != nil {
 		pipeline.AddStage(osbuild.NewGcpGuestAgentConfigStage(p.GCPGuestAgentConfig))
 	}