smcposix: pass unicode as first argument to array.array
This is an instance where we can safely convert the first argument, rest are
the cases except one where we are using 'c' which is not there in Python 3. So
that needs to be handled differently. This will help in making `hg help` run on
Python 3.
#
# Avoid interference from actual test env:
unset HGTEST_JOBS
unset HGTEST_TIMEOUT
unset HGTEST_PORT
unset HGTEST_SHELL