fix: xen not returning absolute block device paths for vdisks

ccnode/libvirtwrapper.py

@@ -760,6 +760,12 @@ class LibvirtVm(VM):
                         elif d_type == 'block':
                             d_path = xdisk.getElementsByTagName('source').pop()\
                                                             .getAttribute('dev')
+                            # FIXME sometimes xen do not report '/dev/' at the
+                            # beginning of block devices, and relative paths
+                            # are non-sense
+                            # Example: vg/myvm instead of /dev/vg/myvm
+                            if d_path[0] != '/':
+                                d_path = '/dev/' + d_path
                         # search the volume object
                         if d_type in ['file', 'block']:
                             volumes.append(self._hv_handle._sto_handle