quated res, to maki it a string, not a number - can only concatenate str (not int) to str

classes/elphel-misc-functions.bbclass

@@ -15,7 +15,7 @@ def version_update(path,file,evr):
     try:
         arr[evr]
     except IndexError:
-        if (evr==1): res = 0
+        if (evr==1): res = "0"
         if (evr==2): res = revision_update(path,file)
     else:
         res = arr[evr]