Add _create_volume to ThinLVMVolumeDriver

Previously, _create_volume from LVMISCSIDriver would be called
when the volume manager calls create_volume_from_snapshot.

Fixes bug: 1192601

(cherry picked from commit 79a402d)

Conflicts:
	cinder/volume/drivers/lvm.py

Change-Id: I5cca287e8204c4647a5f09df961d9a76d0b38c42

cinder/volume/drivers/lvm.py

@@ -630,14 +630,16 @@ def _do_lvm_snapshot(self, src_lvm_name, dest_vref, is_cinder_snap=True):
             self._try_execute('lvcreate', '-s', '-n', new_name,
                               src_lvm_name, run_as_root=True)
 
-    def create_volume(self, volume):
-        """Creates a logical volume. Can optionally return a Dictionary of
-        changes to the volume object to be persisted."""
+    def _create_volume(self, volume):
         sizestr = self._sizestr(volume['size'])
         vg_name = ("%s/%s-pool" % (FLAGS.volume_group, FLAGS.volume_group))
         self._try_execute('lvcreate', '-T', '-V', sizestr, '-n',
                           volume['name'], vg_name, run_as_root=True)
 
+    def create_volume(self, volume):
+        """Creates a logical volume."""
+        self._create_volume(volume)
+
     def delete_volume(self, volume):
         """Deletes a logical volume."""
         if self._volume_not_present(volume['name']):