Don't kill tempmon client if DB session.commit() fails

let the daemon keep trying just like when device.read() fails

rattail_tempmon/client.py

@@ -92,9 +92,8 @@ class TempmonClient(Daemon):
                 try:
                     session.commit()
                 except:
-                    # TODO: pretty sure we need to add a retry for this..
-                    log.exception("failed to commit changes to database")
-                    raise
+                    log.exception("Failed to read/record temperature data (but will keep trying)")
+                    session.rollback()
 
             finally:
                 session.close()