Revert "Add HOSTNAME to env by default for pod containers"

This reverts commit 4c3e195db3.

Signed-off-by: Lantao Liu <lantaol@google.com>

pkg/server/container_create.go

@@ -342,8 +342,6 @@ func (c *criService) generateContainerSpec(id string, sandboxID string, sandboxP
 	for _, e := range config.GetEnvs() {
 		g.AddProcessEnv(e.GetKey(), e.GetValue())
 	}
-	// add the HOSTNAME variable to the environment to match Docker runtime default
-	g.AddProcessEnv("HOSTNAME", sandboxConfig.GetHostname())
 
 	securityContext := config.GetLinux().GetSecurityContext()
 	selinuxOpt := securityContext.GetSelinuxOptions()