Overhaul of anti-virus script

[chrisgilmerproj]

Description

While assessing #3677 I saw some pretty major structural changes that needed to be addressed. A couple things this does:

• Copies the retry logic from [WIP] Add loop to retry where antivirus fails in clamav #3677
• Moves a section of code that waits for the service to be stable up into the retry logic and blocks, which forces us to look for the one signal that should tell us if we can continue: /tmp/clamd.sock. This may increase the time on CircleCI by up to a minute or longer but I think it's a valuable tradeoff.
• Fix the docker inspect code to work properly since it only returns string values of true or false
• Added virus signatures to ignore
• Fixed permissions with regards to virus database
• Reload the virus databases after they've been updated with the virus whitelists
• Fix an annoying warning about a deprecated line in /etc/clamav/clamd.conf which causes confusion when folks diagnose problems with this script
• Added a bunch of timestamp information to make it easier to know elapsed time of different processes

I'm also personally tracking mko-x/docker-clamav#39 which talks about how the software being loaded is an outdated version, which may be the cause of some intermittent flakiness.

Honestly the next time I have to touch this will be to make it a separate repo so I can use it in several places across Transcom's git projects. Hopefully this will keep us stable for a while.

Setup

Try it yourself!

make clean anti_virus