procutil: move assignments closer to reassignments
Doing reassignments is an anti-pattern IMHO, but I see how it makes sense here.
When first looking at this code after jumping here with ctags, I missed the
fact that stdout was reassigned. To make the code clearer, the assignments
should be as close as possible to the reassignments.
#
# Avoid interference from actual test env:
unset HGTEST_JOBS
unset HGTEST_TIMEOUT
unset HGTEST_PORT
unset HGTEST_SHELL