[Python-mode] WRT parenthese errors in Python edits

[Andreas Röhler]

Hi Barry, hi list,

r1449, while fixing lp:1294478, introduced a new behavior WRT to missing parenthesis.

   `py-end-of-statement' will stop at the end of line with related open paren.

   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.


Comments welcome.
Maybe py-verbose-p isn't right here, need a `py-error-p'?

Cheers,

Andreas