Make code to detect Linux distro info more robust. #3854

Previously we just inspected the /etc/issue file. Now we will also
look into /etc/redhat-release and/or /etc/issue.net to see
if we can find what we need.
Add version history items for #3847 and #3780
Merge branch 'V8_0_2-branch' into V8_0-branch
Merge branch 'V8_0-branch'