Fix Python 3 compatibility issue

see error posted in LHCBDEP-4534

scripts/addrel.py

@@ -196,19 +196,7 @@ versions = []
 for dir in os.listdir(lhcbsitelocation + "releases/"):
     m = version_regex.match(dir)
     if m != None:
-        v = []
-        if m.group(1) != None:
-            v.append(int(m.group(1)))
-        else:
-            v.append(m.group(1))
-        if m.group(2) != None:
-            v.append(int(m.group(2)))
-        else:
-            v.append(m.group(2))
-        if m.group(3) != None:
-            v.append(int(m.group(3)))
-        else:
-            v.append(m.group(3))
+        v = [int(g) if g is not None else 0 for g in m.groups()]
         v.append(dir)
         versions.append(v)
 
@@ -236,19 +224,7 @@ if branch != "":
     for dir in os.listdir(lhcbsitelocation + "releases/" + branch):
         m = version_regex.match(dir)
         if m != None:
-            v = []
-            if m.group(1) != None:
-                v.append(int(m.group(1)))
-            else:
-                v.append(m.group(1))
-            if m.group(2) != None:
-                v.append(int(m.group(2)))
-            else:
-                v.append(m.group(2))
-            if m.group(3) != None:
-                v.append(int(m.group(3)))
-            else:
-                v.append(m.group(3))
+            v = [int(g) if g is not None else 0 for g in m.groups()]
             v.append(dir)
             versions.append(v)