py-mark-def hangs, lp:1294478

fixed

As the hang was caused by an missing parenthesis, the proceeding
WRT kind of error is the following:

`py-end-of-statement' will stop at the end of line.

When `py-verbose-p' is `t', an error message tells the reason.

All other commands dealing with whole blocks will
perform normally, but also issue an error-message, if
`py-verbose-p' is on.