Record user running the script with $SUDO_USER or similar (install_bigfix)

[jgstew]

ed84f79#diff-5352e955d46d92a3a800ff8aa617565c

I added this to the code, but it seems to not work correctly within docker containers, or perhaps not at all. Haven't had it work yet on any system.

[jgstew]

I just checked this, still not working for docker.

The output is empty: _BESClient_InstallTime_User=

This may be because there is no sudo user in the case of docker.