Revert "vm: Autoload (gnu build vm)."

This reverts commit a67c00f4f7 in an
attempt to fix <http://issues.guix.gnu.org/48496>.

gnu/system/vm.scm

@@ -35,7 +35,8 @@
   #:use-module (guix base32)
   #:use-module ((guix self) #:select (make-config.scm))
 
-  #:autoload   (gnu build vm) (qemu-command)
+  #:use-module ((gnu build vm)
+                #:select (qemu-command))
   #:use-module (gnu packages base)
   #:use-module (gnu packages bootloaders)
   #:use-module (gnu packages cdrom)