xen_sxpr: set disk type to BLOCK when driver is not tap or file

When parsing disk s-expression to virDomainDiskDef structure, explicitly
set type to VIR_STORAGE_TYPE_BLOCK for all drivers except 'tap', 'tap2',
and 'file'. This was implicitly done prior to commit 9673418c.

https://bugzilla.suse.com/show_bug.cgi?id=938228

Index: libvirt-3.9.0/src/xenconfig/xen_sxpr.c
===================================================================
--- libvirt-3.9.0.orig/src/xenconfig/xen_sxpr.c
+++ libvirt-3.9.0/src/xenconfig/xen_sxpr.c
@@ -501,10 +501,11 @@ xenParseSxprDisks(virDomainDefPtr def,
                        omnipotent, we can revisit this, perhaps stat()'ing
                        the src file in question */
                     virDomainDiskSetType(disk, VIR_STORAGE_TYPE_FILE);
-                } else if (STREQ(virDomainDiskGetDriver(disk), "phy")) {
-                    virDomainDiskSetType(disk, VIR_STORAGE_TYPE_BLOCK);
                 } else if (STREQ(virDomainDiskGetDriver(disk), "file")) {
                     virDomainDiskSetType(disk, VIR_STORAGE_TYPE_FILE);
+                } else {
+                    /* Set type to BLOCK for drivers != {tap,tap2,file} */
+                    virDomainDiskSetType(disk, VIR_STORAGE_TYPE_BLOCK);
                 }
             } else {
                 /* No CDROM media so can't really tell. We'll just