Clean lvm metadata after creating partitions

Run erase_lvm_metadata() after we create all the needed partitions
to make sure we don't have any old LVM data.

We also need to clean old filesystem from newly created partition,
that may retain after previous deployments.

Change-Id: I6ee241aca94a4db7bae2b359af7244dee6a53150
Closes-bug: #1323707

deployment/puppet/cobbler/templates/scripts/pmanager.py

@@ -839,6 +839,12 @@ class PreseedPManager(object):
                 self.late("cat /proc/mdstat")
                 self.late("cat /proc/partitions")
 
+                # clear any fs info that may remain on newly created partition
+                self.late("dd if=/dev/zero of={0}{1}{2} bs=1M count=10"
+                          "".format(self._disk_dev(disk),
+                                    self._pseparator(disk["id"]),
+                                    pcount))
+
                 if part.get("file_system", "xfs") not in ("swap", None, "none"):
                     disk_label = self._getlabel(part.get("disk_label"))
                     self.late("mkfs.{0} {1} {2}{3}{4} {5}"
@@ -997,8 +1003,9 @@ class PreseedPManager(object):
         self.erase_partition_table()
         self.boot()
         self.os()
-        self.lv()
         self.partitions()
+        self.erase_lvm_metadata()
+        self.lv()
         self.late("apt-get install -y grub-pc", True)
         self.late("sed -i "
                   "-e 's/.*GRUB_TERMINAL.*/GRUB_TERMINAL=console/g' "