update.py: fix Ctrl+C handling during layer update

We do not want to continue on to the next layer on Ctrl+C.

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>

layerindex/update.py

@@ -518,6 +518,10 @@ def main():
                     transaction.rollback()
                 else:
                     transaction.commit()
+            except KeyboardInterrupt:
+                transaction.rollback()
+                logger.warn("Update interrupted, changes to %s rolled back" % layer.name)
+                break
             except:
                 import traceback
                 traceback.print_exc()