gnu: virt-manager: Don't propagate qemu.

The current version of virt-manager does not directly use "qemu-img" or
"kvm-img" in its source.

* gnu/packages/virtualization.scm (virt-manager)[propagated-inputs]: Move qemu
to…
[inputs]: …here.

Change-Id: I87a549b4d4f14168419ce419cb92dbf078c35381

gnu/packages/virtualization.scm

@@ -1692,11 +1692,9 @@ (define-public virt-manager
            python-pycairo
            python-pygobject
            python-requests
+           qemu
            spice-gtk
            vte))
-    ;; virt-manager searches for qemu-img or kvm-img in the PATH.
-    (propagated-inputs
-     (list qemu))
     (native-inputs
      (list `(,glib "bin")               ; glib-compile-schemas
            gobject-introspection