Add disk allocation type constants.

coriolis/constants.py

@@ -63,6 +63,9 @@ DISK_FORMAT_QCOW2 = 'qcow2'
 DISK_FORMAT_VHD = 'vhd'
 DISK_FORMAT_VHDX = 'vhdx'
 
+DISK_ALLOCATION_TYPE_STATIC = "static"
+DISK_ALLOCATION_TYPE_DYNAMIC = "dynamic"
+
 FIRMWARE_TYPE_BIOS = 'BIOS'
 FIRMWARE_TYPE_EFI = 'EFI'