Bugfix for solaris in replwrap.bash()

Forgot to set ``echo=False`` when calling spawnu()
directly in replwrap.bash(), resulting in IOError
on SunOs:

    IOError: [Errno 22] Invalid argument: setecho() may not be called on this platform.
Merge pull request #143 from pexpect/setecho-in-bash-replwrap-sunos

Bugfix for solaris in replwrap.bash()