Ask to drop the advertisement clause in blowfish source

[Nicolas Mora]

Hello,

The blowfish source code included in libssh2 uses the original BSD 
license with the advertisement clause:

  * 3. All advertising materials mentioning features or use of this software
  *    must display the following acknowledgement:
  *      This product includes software developed by Niels Provos.

This clause makes it incompatible with the GPL license apparently.

Niels was asked to remove this clause for the pyca/bcrypt project, and 
he agreed: https://github.com/pyca/bcrypt/pull/170

I'm wondering if removing this clause could also be asked for libssh2?

/Nicolas