Make the second arg to the sudo auth verify function const.

This may be either a plaintext password or a password prompt.
Either way it should not be modified by the verify function.

plugins/sudoers/auth/aix_auth.c

@@ -229,7 +229,7 @@ sudo_aix_change_password(const char *user)
 }
 
 int
-sudo_aix_verify(struct passwd *pw, char *prompt, sudo_auth *auth, struct sudo_conv_callback *callback)
+sudo_aix_verify(struct passwd *pw, const char *prompt, sudo_auth *auth, struct sudo_conv_callback *callback)
 {
     char *pass, *message = NULL;
     int result = 1, reenter = 0;