channel_request_pty_size: fix reqPTY_state
channel_request_pty_size: fix reqPTY_state

The state variable isn't properly set so every other call to the
function fails!

Bug: http://libssh2.org/mail/libssh2-devel-archive-2010-12/0096.shtml
Reported by: Steve Legg

libssh2/libssh2,libssh2/libssh2,libssh2/libssh2,libssh2/libssh2