MFT: Quote filenames
MFT: parallel_exec: Fix to not disable 'set -e' in child cmd due to ||

This set -e juggling is to keep this function portable to other
scripts that may or may not be running set -e.

This fixes compute_deps() finding invalid port origins and not
properly stopping before the build starts, which can lead to
infinite loops
MFT: jail/ports -u: Always try upgrading the SVN checkout before updating