anaconda: switch default partitioning scheme to LVM Thin Provisioning

Rework of previous work done by Marek Marczykowski-Górecki (marmarek).

QubesOS/qubes-issues#2412

pyanaconda/installclasses/qubes.py

@@ -23,6 +23,7 @@
 from pyanaconda.product import *
 from pyanaconda.core.i18n import N_
 import pyanaconda.platform
+from pykickstart.constants import AUTOPART_TYPE_LVM_THINP
 
 from blivet.size import Size
 from pyanaconda.platform import platform
@@ -57,6 +58,9 @@ def configure(self, anaconda):
         auto_part_proxy = STORAGE.get_proxy(AUTO_PARTITIONING)
         auto_part_proxy.SetEncrypted(True)
 
+        # Make LVM Thin the default for autopart
+        auto_part_proxy.SetType(AUTOPART_TYPE_LVM_THINP)
+
         # Make disabled NTP by default
         timezone_proxy = TIMEZONE.get_proxy()
         timezone_proxy.SetNTPEnabled(False)