Re: http getpass function in msysgit

 - If GIT_ASKPASS is not set:

  - If SSH_ASKPASS is present, then use that from getpass() for any and
    all places that would want to get "password" like things;

  - Otherwise consult the terminal as before;

 - If GIT_ASKPASS is set:

  - If SSH_ASKPASS is not set, then export the value of GIT_ASKPASS as
    such as well, so that whenever we spawn "ssh", the same GIT_ASKPASS
    program will be used as a fallback.

That way, if the user already has set up SSH_ASKPASS, we will use the same
familiar dialog without forcing the user do anything extra.  If the user
only sets GIT_ASKPASS without doing SSH_ASKPASS, we would also use it to
drive the ssh session.  In either case, the user doesn't need to worry
about multiple configuration or dialog interface.

quoted

It is nice to use one dialog for all cases. git-svn also have the same problem.

Can we direct use SSH_ASKPASS for all getpass and don't use GIT_ASKPASS at all?
The logic will be come simple.