References: bsc#989639
When the device added is a cdrom device (/dev/sr0), don't use
"phy" as the driver name but instead use "qemu".

Index: virt-manager-1.5.0/virtinst/devicedisk.py
===================================================================
--- virt-manager-1.5.0.orig/virtinst/devicedisk.py
+++ virt-manager-1.5.0/virtinst/devicedisk.py
@@ -561,7 +561,8 @@ class VirtualDisk(VirtualDevice):
         # Recommended xen defaults from here:
         # https://bugzilla.redhat.com/show_bug.cgi?id=1171550#c9
         # If type block, use name=phy. Otherwise do the same as qemu
-        if self.conn.is_xen() and self.type == self.TYPE_BLOCK:
+        if self.conn.is_xen() and self.type == self.TYPE_BLOCK and not \
+           self.is_cdrom():
             return self.DRIVER_NAME_PHY
         if self.conn.check_support(
                 self.conn.SUPPORT_CONN_DISK_DRIVER_NAME_QEMU):