Fixed a typo bug in twintest part of GtAssembleVol3D - taken from in813 experience.

Signed-off-by: Andrew King <andrew.king@esrf.fr>

5_reconstruction/GtAssembleVol3D.m

@@ -652,7 +652,7 @@ classdef GtAssembleVol3D < handle
             % need to search symmetry equivelents for the minimum misorientation
             rot_offset = zeros(1, 24);
 
-            for k = 1:length(symm)
+            for k = 1:length(obj.symm)
                 g1equiv = g1 * obj.symm(k).g3;
                 netg = g1equiv \ g2;
                 rot_offset(k) = sum(diag(netg));