Added test_err_redirection_actual_file unit test.
Added test_err_redirection_actual_file unit test.

jakirkham/sh,rdhyee/sh,germangh/sh,ppannuto/sh,simudream/sh,rsmith31415/sh,lwgarmstrong/sh,achernet/sh,hacosta/python-sh,twocngdagz/sh,pdelong42/sh,amoffat/sh,pombredanne/sh,Stupeflix/sh,hacosta/python-sh,amoffat/sh,z-fork/sh