return code from function write() isn't supported

[maar]

Hello,

I've worked with this library in my project. Sometimes this library
was making crash all process/application. I've discovered problem in
function write(). When connection is reseting by peer than function
write() returns '-1' but this return code is not supported by libcli.
That's the reason why it is making crash. I've idea how to handle this
issue. I will send my patch within a week.

Marcin