Updates to upgrade.sh.
1. Move sourcing of p4_vars values before $Log definition so that the instance's log path is used rather than always writing to /tmp. This aligns with the help info for the -L flag.
2. Expose the path to $TmpFile_1 as part of the 'p4 upgrades' step so users easily know where to go look if the process is taking longer than they'd expect rather.