Switched qvm-move-to-vm.{gnome,kde} scripts to use bash not sh

Both these scripts contain `pipefail` which is a bash option and will
fail in dash

(cherry picked from commit 53fc7955f9)

qubes-rpc/qvm-move-to-vm.gnome

@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 #
 # The Qubes OS Project, http://www.qubes-os.org
 #

qubes-rpc/qvm-move-to-vm.kde

@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 #
 # The Qubes OS Project, http://www.qubes-os.org
 #